Rarity sat alone in her bedroom in Canterlot Boutique, the original Ponyville branch of the various fashion shops that she was the proud owner of, listening to her filly sister Sweetie Belle moaning in the next room over. She knew she was quite obviously masturbating instead of sleeping like she'd been told to, not oblivious to the difference between painful moans and those of pleasured frustration. That fact, however, did not excuse the fact that Sweetie should have been asleep over an hour before then.

"Oh that young mare..." Rarity huffed as she levitated off her reading glasses and put them on the table, turning off the sewing machine as she left it. She had a large number of orders of her Spring lineup being waited on by very important clients, dresses and suits for a very important ball soon to take place in Canterlot, and she was drastically behind because of tending to her 'seasonal needs', as she called them.

As she rose from the cushion she was seated on, Rarity tried hard to ignore how her rump stuck to it with the dried remains of her sexual fluids. Tried hard to ignore the fresher fluids which formed a wet spot on the cushions, and how she'd have to launder them later.

She tried to ignore the way her thighs rubbed together as she walked. Tried to ignore how the vibrations it made as her hooves impacted the floors stimulated some very hypersensitive areas. But it all made her all that more aware just how much she needed to tend to herself later. "After this, I think I need to take some more 'me' time. Then when I can think more clearly, I can finish this order," she whispered, as if rationalizing her behavior to herself, "But first..."

Rarity walked down the hallway leading towards the guest bedroom, which was basically Sweetie's room there as much as she slept over while her parents were traveling, and the moans were growing louder the closer she got. Rarity could hear the desperation and urgency in them, so much so that they almost made it sound like Sweetie Belle was in pain.

Standing outside Sweetie's door, Rarity debated how to approach this situation. Surely Sweetie was in a compromising position given the season, and Rarity didn't want to simply go in, ask her to go to bed, and kiss her good-night as she may usually do, nor did she simply want to yell it though the door. Eventually, she simply knocked.

"G-Go away!" a small, squeaky voice from the other side of the door squealed, a loud clatter of something hitting the floor...and vibrating against the hard material.

"Sweetie Belle, dear, are you alright? You were supposed to be in bed over an hour ago," Rarity asked in a kind yet stern voice through the door.

Silence.

"Sweetie Belle, are you alright?" Rarity asked again, but all she could hear was the muffled vibrating sounds, before they suddenly stopped and the frustrated, unpleased moans continued.

"Why can't I just..." Sweetie said, though Rarity knew she wasn't talking to her.

"Sweetie?"

"I just...j-just need one..."

"Sweetie."

"...and I'll probably be OK. C'mon, c'mon, so close...!"

"SWEETIE!"

"WH-AT?!"

Rarity was taken aback by the strength with which the squeaky voice within the room spoke those words, the force of the tone making Sweetie's voice crack at the end. Sweetie hadn't raised her voice to Rarity since their last argument years ago when Sweetie declared them 'not sisters', only to make up with her once they'd competed in the Sisterhooves Social as a team and finished it together.

Rarity was so taken aback, that she wasn't sure how to react. An angry response would only make things worse, Rarity knowing all too well how hormonal a mare in heat could get and not wanting to be the cause of another big fight between her and her sister. Then too, she couldn't simply let her sister's outburst go unchecked either. "Sweetie Belle!" Rarity admonished, hearing the moaning pause for a moment.

"Please...please, just one..." Sweetie said again, sounding distant, distracted, as though she wasn't even aware of snapping at her sister seconds ago anymore. Then Rarity heard her whimper, then sniffle, before her sister apparently started to cry. Pillow-muffled wails of frustration and the anger thereof were clear for Rarity to hear, and it honestly broke her heart, "...please...please..."

"Sweetie, may I...may I come in please? We need to talk," Rarity said, deciding perhaps she should go talk to her sister after all. Though really, something else was deciding for her to go in that room. Her instincts were well aware of what could happen if she did.

"I'm coming in," Rarity said as she slowly twisted the handle. She wasn't sure if Sweetie heard her, but she exercised her right as her guardian to enter after knocking.

The first thing that hit her as she cracked opened the door was the smell. It was a deeply rich, almost sweet, musky scent, and it hit her like a hammer to the muzzle. Rarity almost recoiled at its pungency but didn't because of the intertwined allure of it; the scent of both a virile stallion and fertile mare, both mixed with her sister's own unique scent. The primal scent of a pony wanting to both breed and be bred all at once.

Rarity almost coughed as the duel pheromones invaded her muzzle, nearly strong enough to burn the inside of her nose and throat alike. "Dear Celestia..." Rarity mumbled to herself, covering her nose with a piece of cloth she quickly tore by magic from one of the discarded bolts in the hallway. Rarity easily determined Sweetie was in her first heat, and she had it very bad.

Clearly oblivious to her door opening, Sweetie continued her self-ministering with her eyes sealed shut from both pleasure and concentration. Rarity's jaw nearly dropped as she first saw it.

Sweetie's member was quite sizable for such a petite young mare, looking quite out of place on the young teen mare at all. The light-gray shaft was coated in what was either her precum, her clear feminine fluids, or both, letting Sweetie press it between the frogs of both of her hooves and stroke it up and down its length.

While not quite the size of a full-grown stallion's, her colthood was certainly above what a colt her age would be packing, and would likely grow into quite an impressive stallionhood as she got older.

Beneath Sweetie's member were a pair of equally swollen balls in a light-gray scrotum covered with fur the same white as her coat, looking in proportion with her shaft; big for her age.

As if that wasn't enough, Rarity saw Sweetie's light-green magic fumbling with a vibrating stallion dildo she'd clearly 'borrowed' from Rarity's room at some point, barely prodding her slit's light-gray lips with it, let alone penetrating herself.

Rarity had never seen her sister fully erect or wet like this before. She had known Sweetie Belle was a hermaphrodite since she was born, one of the rare mares who has both a fully-functional male and female reproductive system. It was an exceedingly uncommon recessive trait from her mother's side of the family, Rarity learned, that usually came about only around once every few generations, even in foals born from those who possessed that trait dominantly.

Sweetie Belle was apparently a 'lucky one' as their mother, Cookie Crumbles, liked to point out, much to Sweetie's chagrin at even having her 'boy parts' mentioned. Whether her mother was serious about her being lucky or not, Rarity could never tell.

Clearly, Sweetie's stallion part was rather aroused too because of her being in estrus or her female parts being so in need, the mental pathways between her sexual organs possibly interconnected somehow. Rarity couldn't really remember now as she saw what Sweetie was still doing.

Rarity guessed Sweetie's magic was weak from lack of concentration given she was only giving herself a weak prodding despite undoubtedly wanting more. Her mental energies were probably focused on finding a real stallion or colt and presenting to him, or perhaps a cute little filly she could slide inside of. Or possibly both at once.

Ironically, a similar fantasy was meanwhile playing out in Sweetie's mind.

Sweetie was pinned beneath Button Mash as he mounted her, feeling his hard colthood slamming into and spreading her flower, making it bloom in the best way possible. Meanwhile Dinky Doo was beneath her and getting the same treatment Sweetie was, Sweetie's dick buried deep inside the warm, soft, tight filly...

Sweetie had heard the insides of a mare described as 'soft' and 'warm' from some of the colts who were bragging about 'getting some' with the other fillies. 'Soft and warm, and really tight'. She tried to imagine what it was like, her member being wrapped around by a warm, soft...something.

Getting an idea, Sweetie grabbed her silky satin blanket between her wet hooves and, without thinking about it, wrapped it twice around her filly-cock and started pumping. Instead of the life-changing sensations she'd expected, after a few pumps, the smooth blanket simply bunched up between her hooves. "Uuugh, dumb fabric*!" Sweetie yelled, before throwing the blanket across the room as hard as she could.

The blanket, saturated with pre-cum, flew across the room...and managed to hit Rarity in the face, draping off her horn and dangling in front of her nose. The musky scent of a seemingly quite virile stallion instantly filled her muzzle as her nostrils flared, whiffing deeply of the scent of...her sister's dick!

As Rarity remembered just where what she was smelling came from, she gave a startled yelp. "Eeeeew~!" Rarity squeaked in a quite undignified, and very unladylike, squeal as she fruitlessly batted at the blanket, tangling herself up in it as she flailed to get it off. "Eeew-ew-ew-eeeew-get-it-off!" Seemingly forgetting her magic in the moment of panic to get the soiled cloth off of herself, Rarity pawed at it with her hooves, unintentionally inundating her fur with her sister's scent before she finally managed to throw it off.

Chest heaving, Rarity felt her mind fogging over as her breeding instincts started to take over, the pheromones of a stallion doing their work on her heat-addled brain. She could feel herself grow even wetter under her tail, the excess drooling down her inner thighs and soaking into the fur there; her clit winked, her breaths deepening, her hind legs wanting to lock up to support the stallion who was inevitably going to mount her any second.

Sweetie watched all this, her own nostrils flaring as she smelled a pony in heat so near her, her own estrus scent not even recognized by her stallion mind as a breeding partner. This deep, rich smell, however - this instinct-devised beacon - called to her olfactory sense, telling her there was a fertile mare nearby, the light neon hint identifying her as a unicorn. Her instincts told her to find the fecund pony and mount her, to breed her and pass her genes on to the next generation of ponykind.

**Sweetie furiously beat her hard-as-concrete colt-meat, such a feral feat caused by her sister's heat and honey-sweet-smellin' treat, her sperm ready to sow like grains of wheat into peat.

Rarity's womb's on preheat, ready to be bred in a beat, Sweetie ending her torturous heat, with semen thick as sleet.

Sweetie-seed ready swim in a fleet, swim with the speed of an athlete, to compete down that one-way-street, for an egg ready to meet and greet then take a seat; to transmeate being two simple gamete. Makin' her sister's womb with foal; replete.

Foal starts out one cell in the oviduct discreet, livin' in its eleven-month suite, a womb for sure no oubliette. Its heartbeat and movements soon not discreet, thrummin' upbeat; its conception, bittersweet, and after birth a foal, petite but complete, w'll suckle on her teat.**

Just as before, Sweetie simply couldn't tip over her edge by her own means. Flustered once more, Sweetie released her cock from between her hooves, giving a growl of frustration as the perpetually, painfully plumped phallus pulsated pervasively, practically painful, in its problematic proclivity to procure position in a pussy pre-pulsations of procreation.***

"I just...I just can't..." Sweetie said sadly, her colthood twitching every couple seconds, imbuing her lower chest's fur with precum.

Rarity, meanwhile, was feeling much the same, struggling not to touch herself. Then she got an idea. It was likely just her hormones talking, her mind addled by estrus, but she walked to the bed and nudged Sweetie over on the bed. "Hey!" Sweetie yelped as she was moved, a not entirely pleasant shudder going down her spine as her hypersensitive body was touched. What happened next, Sweetie did not expect.

Rarity climbed on the bed with Sweetie after making room for herself, leaning her back on the pillow that was against the headboard, her croup on the bed, and spreading her hind legs while using her forelegs to support the awkward position. Instantly the scent of her estrus intensified as she opened her legs, making Sweetie whimper as her hips jerked into the air all on their own. "R-Rarity, what are you doing? You're making it worse!" Sweetie exclaimed, looking over to her sister with a helpless expression.

In the back of her mind, Rarity knew this was wrong, but also knew that she, the Element of Generosity, couldn't simply leave her sister in such a state as this. Instead, she decided, she'd give the most precious gift she could to her sister while she was in a state like this.

Herself.

Sweetie looked at Rarity in disbelief as she laid on the bed beside her, Sweetie on her back, her fillycock like a mage's spire above her. "Mom told me I need to stay away from mares and fillies that s-smell good like you do, that I can get them p-pregnant if I put my...my penis in them. Like, with a foal!" Sweetie said even as she stood up, but the urge to climb over her sister and just put her penis inside her despite that fact was nearly overpowering, and possibly indeed because of it.

"It's OK Sweetie, it'll all be OK. I'll take good care of you, little sister," Rarity cooed, losing herself to her lust as she looked down, seeing her little sister's member throbbing in need. One part of her mind recoiled in recognition that this was her sister's cock, but the greater majority of her brainpower was now on simply getting bred. "Just come here, climb over me, and do what your body tells you to."

Rarity usually liked to take things slow with a stallion, to have long, extended foreplay with oral and sensual massages. This time, she didn't want any of that. She wanted to be fucked raw and hard, now.

"B-But Rarity..." Sweetie countered weakly, but the offer was getting too hard to resist as she stood and looked down at her sister's crotch. Rarity's light-gray lower lips were swollen with arousal and shiny with her fluids, its bottom pouting up into a cleft where her clit was hidden away. As she winked that clit, exposing her deep-pink inner self, Sweetie lost it.

As though being drawn over by invisible forces, Sweetie walked over to Rarity, climbing over her larger sister and rested her forehooves on her sibling's belly, mounting her. By chance, her member was aligned perfectly to Rarity's snatch, the flare pressed to those puffy, wanting lips. She looked up to Rarity, saw her nod her permission, and like that Sweetie was lost to her instinct. "A-Are you sure this is OK?" she asked, but her pelvis was already moving without her conscious input.

"Ooooh Sweetie yes~!" Rarity cooed as Sweetie pressed her hips forward, feeling her flare penetrate past her outer lips with no resistance. This was exactly what she needed, she thought, feeling as Sweetie slid more and more of her length into her, spreading her passage open just like her instincts demanded.

Sweetie gritted her teeth as she felt herself enter her sister's nearly hot insides, losing her male virginity just like that. She was soon completely lost to the sensations of entering her first mare. It was soft and smooth like her blanket felt, but had these little ribs in it that added so much more sensation, and was so much warmer than the cold cloth too. It was tight and moved too, squeezing down on her even as she entered, as well as very slick and wet inside. "R-Rarity~!" Sweetie coed back, not able to do much more as she sunk inch after inch of her needing shaft into her sister's equally needing insides.

After a moment, Sweetie hilted into Rarity's welcoming body, getting a quiet grunt from Rarity as she felt her sister's balls pressing to her butt. They felt bigger than they looked when touching her like that, her cock feeling even thicker than it looked too when it was instead inside her and stretching her out. Meanwhile, her passage was filled quite contentedly, making Rarity give a happy little sigh.

While her sister's colthood wasn't the biggest thing she'd ever had inside her, living or inanimate, it was still quite sufficient for her needs. The fact that it belonged to somepony very close to her only added to the feelings it gave her. "OK Sweetie, just pull your hips back, push them forward, and keep doing that..." Rarity whispered, seeing and feeling Sweetie nodding her head while she laid it on her big sister's chest.

Sweetie gave a quiet 'aah!' as she pulled out an inch, only to slam back in hard, her instincts demanding she keep deep inside this fertile mare. She kept up those shallow, unsteady humps for a while, before Rarity's horn lit on a back stroke.

Sweetie felt as Rarity's magic eased around her hips, pulling them back more, pulling her out of her sister's warmth. The loss of that feeling around her was like Sweetie was losing a vital part of herself, her hips feebly trying to push forward again even as she was pulled out. "Rarity...please..." Sweetie said in the most heartbroken tone Rarity had ever heard, almost like she was going to burst into tears.

"Shh, it's OK," Rarity comforted, "I'm just showing you how much better longer strokes feel. For both of us." As Rarity soon released Sweetie's hips from her magic, the younger mare quickly slammed her hips forward on instinct, her eyes closing as an even stronger sensation came from more of her shaft being stimulated at once.

Sweetie's thrusts became more full after that to Rarity's delight, both savoring the feelings of their parts being stimulated, sharing something special together. It felt so natural, so perfect, yet something was missing for Sweetie. She felt so empty inside her fillyhood. She tried to lift the discarded toy with her magic but her mental grasp on it quickly failed, both because of her still-developing magic, and because being hilted inside a mare's pussy made it very hard to concentrate.

Seeing her sister's intent by the minty-green magic glow on the toy, Rarity lifted it with her own blue magic, Sweetie's eyes following the rather large dong. "Do you want this inside you too, while you..?" Rarity asked simply, instantly getting a nod from the slowly thrusting filly. Without further comment, Rarity then levitated the dildo behind her sister and, using the large mirror at the end of the bed to aim it, easily found her little sister's entrance.

Sweetie moaned as the cool tip of the stallion dildo pressed to her nearly-virgin lips, exactly what her body craved soon to be all hers. She winked against it, trying to ease its penetration, her little pleasure nub tapping against it only adding to the barrage of pleasure she was already feeling.

With practiced ease from her own uses of that and other toys, Rarity slid the dildo a few inches into her sister's needing foal-canal, hearing her gasp as she did. She felt Sweetie stop humping and instead quiver atop her, her cock throbbing in Rarity's pussy, the youth tensed up at the new sensation. "OK?" Rarity asked, only getting a stiff nod from her sister. "More?" Another nod. Rarity proceeded on at the confirmation, sinking more and more black silicone into her sister's inviting pink flesh.

Sweetie, meanwhile, learned what it felt like to be filled in the way she was filling her sister. She'd taken her own physical virginity months before with one of the toys she'd 'borrowed' from her sister's room and had been experimenting, but had been too afraid to go deeper than a couple inches after how much it'd stung then. Now, as she was being stuffed by much more than two measly inches, she felt no pain; only pure bliss. "R-Rari..." Sweetie mumbled, both sets of her instincts now satisfied; a mare beneath her that she filled, and a 'stallion' within her who filled her in kind.

"Well, keep going in and out of me dear. I'll go to your rhythm," Rarity said, her own need being made quite apparent as her stallion sat tortuously still within her, fully within her but not breeding her. Using her magic to give her sister's rump an encouraging pull back again, sliding that glistening dick from her depths, Rarity was pleased as Sweetie thrust it right back into her, sending a tingle of pleasure down both their spines as she did and her giving a contented grunt at the force of the thrust back in.

Sweetie eventually adopted a faster rhythm, her balls making quiet slaps on her sister's soaked ass as she humped away. Rarity made the toy go into the filly as Sweetie unsheathed her colthood from her elder sister's grasping depths, then the filly-fluid-slickened toy slid back out of her when her shaft instead entered Rarity again, constantly keeping the little filly in bliss; always either filling her mare, or being filled by her 'stallion'.

The two sisters kept going at that measured, if sloppy, pace for a while, both simply savoring the sensations of feral breeding, one for their first time, and the other once more. Slick, hot wetness embraced hard, warm thickness for both mares. Rarity squeezed her well-trained, powerful vaginal muscles down on Sweetie's pulsing member as it slid along easily in her well-lubricated depths. Meanwhile, she could feel through her magic as Sweetie squeezed on the toy as it fully penetrated her again, nuzzled right up to her little cervix. "R-Rare...I love you..." Sweetie whispered, before suddenly meeting her lips with Rarity's nose.

Rarity smiled at the cute gesture, seeing Sweetie's face flush a deeper red from what it was the whole time, her eyes averting from her sister's once she pulled her muzzle away. "I love you too, but whatever is the matter, dear?" Rarity asked.

"Well, I meant to...kiss you...on the lips," Sweetie said, before feeling one of her sister's hooves meet her muzzle and guide it back so she was facing her own. Without further ado, Rarity leaned forward and met her lips with Sweetie's, getting a quiet squeal of surprise from her at first, before the filly quickly melted into the kiss. Rarity had taken her penile and vaginal virginity, Sweetie thought, so why not give her her first kiss too. With that, she pushed back into her sister's lips.

The first contact of their lips sent little tingles down Sweetie's spine, adding to those already coming from their crotches' intimate joining, the added stimulus only making her that much more in ecstasy as they kept kissing longer.

They kissed while they fucked faster, Sweetie's hips now working purely on her urges to breed her mare, thrusting away as her instinct demanded, not able to maintain a pattern anymore as a growing desire to stay deep inside that warmth took over. Sweetie felt something happening inside her pelvis as her balls clapped loudly against Rarity's ass with each hilting, a tightness developing at two different points in her body.

Sweetie's inner muscles started squeezing down harder on the pseudo-stallion within them as a tightness grew in her lower belly, her cock throbbing harder into the mare surrounding her cock, feeling another tightness developing at the base of her member as its tip also felt somehow bigger inside her sister. "R-Rarity, s-something's happeniiiiiing~!" Sweetie squealed, her hips jackhammering into her sister, before stopping dead as she forced herself as deep as she could, hilting to the base on that ancient, primal urge of a male to plant their seed as deep as possible; to give it the best chance of taking root in fertile fields.

"It's OK Sweetie, just let it happen. It'll make you feel so much better," Rarity said to her panting sister. Her own release was still a while off, but helping her sister reach her own was her only concern right then.

Rarity started to intentionally squeeze her muscles down on Sweetie's shaft as she felt her little sister's cock start to flare within herself, rather pleasantly spreading her a little more in the process. She meanwhile kept the slow, deep thrusts of the dildo while Sweetie stayed hilted inside her, feeling the filly trembling now, clearly right on the edge.

"I...I c-can't...g-get over..." Sweetie whimpered miserably, the frustration of before building again, the feelings growing evermore intense but never quite enough to set her over the precipice into the ocean of bliss. Thankfully, her sister understood just what she needed.

Using her magic, Rarity quickly captured her sister's pleasure-nub on a wink and started rubbing it in a circular motion, feeling it starting to pulsate spastically as she forced it to stay out of its hood instead of being able to wink, as well as rubbing her balls too. Sweetie started jerking her hips again at the intense pleasure that brought her.

After just a moment of this treatment, Sweetie cried out in absolute bliss as she tensed up again. Her hips were now rapidly jerking her flared member in and out of her sister, her pussy going into spasmodic contractions as she was finally set over into the grand finale she'd edged herself to countless times all night.

Sweetie was overwhelmed by all the sensations, her cock starting to involuntarily throb in a steady, rapid rhythm as warmth surrounded it, her pussy doing the same on the silicone trapped within her vice-like tightness; one working to bring something into itself, the other to expel something, a contradiction that couldn't be more pleasurable.

Eventually it all became too much as she finally set over that final hurdle, Sweetie letting out a long, extended squeal as her body went into a duel orgasm. She felt her passage milking the dildo within her as it tried to extract the virile sperm from her 'stallion' and deep into herself, her cervix reaching down to give its tip kisses to accept its virile gift into her primed foal-oven for eleven months of baking, trying so hard to conceive the foal her young womb so craved. Her slit gave a couple of small spurts of filly-cum out in the process as well, a testament to how good she was feeling.

Meanwhile, Sweetie felt something warm moving up through her shaft then squirting forcefully out from her, gasping as her member spewed forth its first-ever ejaculation, her virile genetic payload spurting deep within her sister, pulse-pulse-pulsing away rapidly as she inseminated her first mare. Sweetie eyes were sealed and jaw locked as she felt so utterly contented now, both sets of instincts now purring with satisfaction at her twin releases. Her head was light and her body trembling at the strength of her pleasure, awash in an ecstasy she'd never felt before tonight, all thanks to the best big sister a filly could ask for.

Having edged herself so much and being in rut, and with her sister's estrus pheromones encouraging production of more sperm and semen from her all day, Sweetie's load was not small by any means. Rarity was easily able to compare its quantity to a full-grown stallion who was pent-up for weeks, able to feel every wet and sticky dollop being launched deep inside her. The size of her spurts and the force with which she gave them also compared the same as a stallion's, making Rarity more than a little impressed...and way more than a little pleasured.

"That's it, my little Sweetie," Rarity cooed as she felt Sweetie's balls twitching against her rump while they pumped her sperm, the pulsations of Sweetie's thrashing breeding tool within her and the wet, filling warmth pooling at its flare all feeling very satisfying to her. "Yes, let it all out. Oh my, you're cumming so much, so hard!" Rarity continued, her heat cooling as the warm semen pervaded ever deeper into her, passing her dilated cervix and entering her ripe-for-foal womb. She used her muscles to intentionally knead and milk everything she could from her little sister, and quickly learned what she had was quite filling.

As Sweetie's orgasms calmed some time later, eventually just pulsing dryly into her for a while, Rarity stopped moving the dildo in her, instead leaving it hilted as far as she could, pressed to the deepest wall in Sweetie's fillyhood. Sweetie went completely limp save her heaving chest, panting through her nose as her mind tried to catch up with her body and comprehend what had just happened to her. "W-woah..." Sweetie said wearily when she had enough of her faculties back to do so, feeling so utterly drained now in more than one way but satisfied, that uncomfortable 'full' feeling in her pelvis and balls gone and replaced with a different one entirely in her vagina.

Sweetie was still hilted into her sister much to her delight, her flare swollen to dam all her sperm into her mare and increase the chances of conception while her own 'stallion' did the same within her.

"My my, that was quite a long orgasm..." Rarity commented, feeling quite pleased herself even if she hadn't gotten a climax of her own yet. Just being filled by a flared cock, feeling her sister's orgasmic pulsations within her, and the foal-cream coating her inside were quite soothing to her needs on their own, not to mention the emotional satisfaction of seeing Sweetie so relieved. "...feeling better?"

"Oh like you wouldn't believe!" Sweetie said, giving a delighted little giggle. She was so utterly giddy and happy right then, yet relaxed too. It was like a ten-thousand pound weight was lifted from her mind, it now feeling as light as a feather. "Thank you Rarity!"

"Oh, it was no problem dear. Now do you think you'll be able to sleep?" Rarity asked, seeing how relaxed Sweetie looked, her eyes already drooping tiredly.

"Yeah, without a doubt," Sweetie replied, before she realized something, "Wait...did you get to feel good too?"

"Yes Sweetie, I got to feel good when you were sliding inside me, and then when you were...ejaculating. It still feels good."

"No, I mean really good. Did you get an...what did teacher call it...an 'orgasm' too?"

"No, Sweetie, I didn't cum."

"Cum?"

"Yes Sweetie, that's what ponies call orgasms generally. 'Cumming' or 'to cum' is having an orgasm, and cum is also a stallion's, or mare's, ejaculate."

"Oh. Did you want to 'cumming', sis? I know you know it feels really good!"

"It's 'to cum' dear, and I can just take care of myself later," Rarity said as she felt Sweetie's member wilting and sliding from her with a quiet schli-pop, the filly's productivity proven as a large dollop of nearly pure-white, sperm-rich semen followed it out. "I don't think your penis in any condition to go again right now."

"But you made me feel so good! I want you to feel that good too, Rarity!" Sweetie said with a huff, reluctantly dismounting her sister.

"It's OK, Sweetie, really."

"What if I used my mouth instead? The colts at school said fillies really like that!"

"I..." Rarity said, before sighing. She really did want to cum after all, so close yet so far, and she was never a mare to refuse a good eating out by her stallion. Or in this case, her special little filly sister. "...oh very well, but what about your...cum?"

Sweetie cringed initially at the thought of putting something that came from her penis into her mouth, but was determined to make Rarity feel as good as she herself had felt. "I'm sure it's not that bad. Other mares eat it all the time in those one magazines and movies!"

Rarity made a note to discuss just how her sister knew so much about that topic more thoroughly with her at a later time, and who had taught her, but for now she just rolled with it. "Well, that's true, but most stallions don't enjoy their own brand, so to speak."

"Well, I'll try anyways. I want you to feel good like I did, even if I have to eat my own...brand," Sweetie said adamantly, before arranging herself so she was behind Rarity, muzzle between her legs, "that felt too good for you not to get one after helping me get mine!"

Rarity meanwhile had slid herself down so she was then laying flat on the bed and her head on the pillow, legs still spread wide to give Sweetie plenty of room to work. "Wow, I put all th~at in there?" Sweetie asked with a small voice crack, looking at her sister's semen-covered petals, still spread slightly and oozing a thin stream of her cum, Sweetie seeing more white mottling the deep pink within and smelling her own masculine part's scent strongly alongside Rarity's heat.

"Mmmhm, you sure did Sweetie darling, and it felt simply divine as you did. Still does," Rarity said, smiling dimly at the lovely, warm, full and slimy feeling still within her, making her insides feel slightly tingly, as well as the memories of Sweetie cumming in her raising her arousal further; "now, would you be a dear and start, if you'd still like to?"

Sweetie looked at her sister's spunk-filled pussy confusedly, before meeting her sister with a similar look. "So...I just lick it?" Sweetie asked, getting a nod from Rarity.

"Well, you can just lick it, sure, but you can also push your tongue inside and lick inside too. Also, at the top is a little nub called a clit that feels really good to be touched too, as you probably learned in your little sex ed class. Something they may not tell you is that it's really sensitive, so only lick it sometimes until the mare's near climax or asks for more, OK?" Rarity explained, getting a nod from Sweetie, "Just do as you please until then, and I'll let you know if you need to change what you're doing or stop."

"OK, here I go..." Sweetie said reluctantly, gulping, before dipping her muzzle down and taking her first lick of sister's and her combined fluids. It tasted...tangy, musky, and sweet she'd say, and a little bitter and salty, though not intolerably so. She licked again, from the bottom of her big sister's slit just short of her anus all the way to its clitoral cleft, hearing Rarity gasp. "Are you OK?" Sweetie asked, getting a nod from Rarity.

"Oh my stars yes I'm good," Rarity replied promptly, her head tilted back. Just those two licks had been heavenly, her already so close from the sex that it wouldn't take much to set her over, "please, do keep going. I'm already...near."

Sweetie nodded, smiled at that news, then continued to lick her sister's filly-cum-covered mons, starting to lick between her folds and making Rarity's back leg twitch as the older mare moaned. Seeing that as a positive sign, Sweetie continued licking along her slit, noticing that her pussy was twitching too, the little nub her sister had mentioned before poking out and showing itself to her rapidly now. "Is that your 'clit' poking out? Why's it moving like that?" Sweetie asked, looking up at her sister, her muzzle wet with her fluids.

"Hah, yeah, that's my clit, and it's moving because I'm 'winking' it. A mare does that when she's feeling really good, or wants a stallion to mount her and make a foal with her. It can be done both voluntarily, and sometimes against her will in climax, when she's extremely aroused, in estrus, or even when passing a particularly attractive stallion in the street."

"But...but I can't mount you again! It's not ready yet! I'm not even 'erect'!" Sweetie said, getting into a small panic. "A-Am I supposed to be? Is something wrong with me?!"

"No, no calm down please, Nothing is wrong with you," Rarity said, diffusing the situation, "My winking just means what you're doing feels really good to me, I'm exposing my most sensitive area for more attention, and I want you to keep going, that's all," Rarity said, Sweetie giving an internal sigh of relief

"As for you not being, ahem, erect, that's your refractory period, a time you can't become...aroused...again after an orgasm so your body has some time to 'refill your tank', so to speak. Darling, you don't need to mount me again until you're ready...and only if you want to. For now though...it feels really good when somepony puts their tongue inside there instead..."

"Oh, OK," Sweetie said simply, calming down again, before going back to work on her sister. Getting the hint when Rarity said it felt good when there was a tongue inside her, Sweetie did just that, penetrating her sister with her tongue and hearing a deep moan from her as her reward. Sweetie too was rewarded, her tongue coated in the thick, lightly-sweet fluids of a fertile mare very near her ovulation, likely hours or even minutes away.

"Mmm, do be a dear and pull back a bit Sweetie, then curve your tongue upwards inside me, towards my belly," Rarity said, before giving an involuntary tremor as Sweetie's tongue grazed just where she wanted it. "A-aaah-yes....right there..."

"Why's right there so special? I thought the clit was the really good part?" Sweetie asked, pulling away to Rarity's slight annoyance.

"Because what you were just licking inside me is my 'G-spot', which is a concentration of nerves that feel really good to be stimulated and is even more sensitive than my clit. Bit of an art form finding it at first, but once you do, hoo the orgasms you can have or gi-give-haaaah..." Rarity answered, before feeling Sweetie's tongue slide back inside her, going right back digging into her G-spot with enthusiasm even as she still spoke, to the elder's delight as her whole body trembled.

Sweetie continued to eat her sister out, using her hooves to spread her sister's pussy or rub at her clit, licking deeper and making small swirls with her tongue-tip against her sister's most sensitive inner area. She learned what Rarity loved most by observing and adapting to her sister's reactions, as well as Rarity's own tips. Only a minute more into the pleasurable sensations, Rarity started to tremble more. Sweetie was able to feel her vaginal walls squeezing down on her tongue, Rarity's breaths getting more shallow. "Are you getting close to a cum?" Sweetie asked the panting, red-faced mare as she paused for breath, getting a nod.

"'C-Close to cumming', and y-yes Sweetie, you're doing very well. Now, can you p-please focus on my clit? I'm so close..." Rarity asked, and instantly Sweetie responded physically.

Sweetie saw the large, heart-shaped nub peek out at her again and took it into her mouth, suckling on it, and Rarity tensed up. After a couple suckles Rarity started squirming beneath her, shivering more. She started letting out a series of constant moans as that pleasure-button throbbed in her sibling's mouth, trying to wink and failing.

Rarity, meanwhile, was overtaken by a very powerful orgasm, unable to really breathe as her body locked up, her inner muscles clenching and unclenching to pull the previously deposited sperm deeper into her womb with constant, rhythmic contractions, some even entering her oviduct to await the soon-coming egg. She felt so blissful, so happy, so satisfied as her little sister brought her to her climax, her estrus now satiated for the moment. Rewarded by her body for letting herself get bred like a good little mare and continuing her species.

Sweetie stopped licking and just watched as her sister's pussy quivered and winked, seeing a couple of squirts of whiteish liquid that wasn't her cum come from it, before looking up and seeing Rarity's face locked in an intense expression. "Are you OK?" she asked, though didn't expect a response if what Rarity was going through was anything like what she herself had experienced minutes before.

Eventually, Rarity's high wore off, Sweetie lifting her head and looking up at her sister. "Did that feel good?" Sweetie asked, getting only a weak nod from the now thoroughly contented mare.

"Yes Sweetie, I'm OK, and yes, that felt divine. Come up here and lay with me please. It's so much nicer to cuddle with somepony after," Rarity replied when she had enough of her faculties back to form words. Sweetie did as asked and moving so she faced her sister. They kissed chastely one more time as they recovered, giving each other just a little more shared pleasure, before Rarity stood.

Sweetie laid on her belly, hooves sprawled out in the bed in absolute comfort, a big, tired smile on her muzzle as Rarity kissed her on the head. "Goodnight, Sweetie~!" Rarity said lovingly, before starting to leave.

"Mmhmm...goodnight big sis, I love you," Sweetie replied, yawning as she closed her eyes.

"I love you too, little sis. Sleep well," Rarity said as she turned out Sweetie's bedroom light, then returned to her dress-making, her mind crystal clear. She'd have to remember to get a 'morning-after' potion tomorrow before she dropped her orders off, she thought, before focusing back on fabric and patterns. A glob of cum soon drooled from her slit, though, and landed on the floor between her hind legs. Rarity winced at the mess, standing. More immediately, she decided, some tissue would be more useful.

She also knew she and Sweetie had much to talk about the next morning; about what happened, and what may come of it. Namely, perhaps more of what they'd just done later on.