“Giddyup!” Twilight squealed in delight, her rigid cock buried in Shining Armor’s ass as he stumbled around the room with her riding on his hindquarters. “Faster slowpoke,” the little purple filly chastised, bucking her hips downward and grinding the head of her shaft against her brother’s prostate.

Shining groaned incoherently, his semi-erect stallionhood leaking precum with each of his sister’s thrusts. He’d been tasked with watching his sister while their parents were out of town for the weekend. Shortly after Twilight Velvet and Night Light had left the siblings fell into a vicious cycle of debauchery, Twilight with her guile and prodigious marecock and Shining with his naivete and love for his sister. To make matters worse Shining Armor had always had an interest in stallions or, more specifically, their equipment. He’d found his mind, and eyes, wandering over the years to the hefty balls and deliciously meaty shafts of his fellow cadets. The last thing he’d expected after returning home for the weekend was to find his sister sporting one of the largest dongs he’d ever seen.

Twilight had always been a dickmare but, apparently, over the past few months she’d really been through a growth spurt. The adorable filly looked like she’d sprouted a fifth leg when she was excited, which was surprisingly often. Even as well educated and intelligent as she was, Twilight was heavily affected by the hormones and urges that her growing body subjected her to. Shining Armor had first assumed that she was simply lacking control although he quickly changed his mind on the matter. Twilight was surprisingly domineering and manipulative, taking note of his reactions, involuntary and otherwise, to various types of stimulation; which had ultimately led to their current situation.

The white stallion, wearing a skirt, leggings, choker, and makeup as his little sister rode him around the livingroom while fucking him silly. Shining Armor trotted around the room, his dick helplessly drooling as it swayed from side to side beneath him.

“You gonna cum for me again Shiny?” Twilight teased, draping herself over his back and whispering into his ear, “You really do make a cute mare.” The word sent a shiver up Shining’s spine, causing his eyes to flutter and his knees to buckle. “Someone like that?” she continued, caressing the side of his neck with a hoof, “Getting made up all pretty and serving marecock from sunup to sundown, your ass and belly full of spunk when you finally get to lay down for the night.” The stallion groaned, visibly trembling as the filly tormented him. “All warm and cozy in bed, your sore jaw and throbbing backdoor reminding you of how much you love being used,” she murmured, giving his ear a nibble. “Cum for me bitch,” Twilight demanded, brutally driving her member into his behind.

Shining Armor’s still semi flaccid stallionhood began feebly spurting cum as his jaw hung open, wordlessly gasping at the carnal abuse he suffered at the hooves of his little sister. It wasn’t the first time he’d cum over the weekend from Twilight ravaging his ass. He just stood there, panting and riding out his orgasm as Twilight continued to slowly drill into his rump. Shining was so enwrapped in the moment that he didn’t even hear the front door as it opened.

“Hi mom! Hi dad!” Twilight cheerfully cried, hopping off Shining’s back and dragging her rod out of his violated ass, leaving it a gaping and drooling cum and lube to the floor below. Twilight Velvet and Night Light stood aghast at the debaucherous sight that greeted them.

“What is the meaning of this?!” Velvet shouted as Twilight galloped over, giving her a hug.

Wearily Shining Armor looked over, his cum addled brain regaining some modicum of composure as he realized his parents had returned early from their trip. “Mom, I…” he croaked, his voice weak and his throat sore from nearly two full days of harsh use.

“Shining was really interested in how big I’ve grown so we’ve been playing games all weekend! Just like you and dad do when you think I’m asleep,” Twilight replied, burying her face in Velvet’s neck.

As Velvet looked at Shining Armor with disgust Twilight shot him a predatory grin; she knew good and well what she was doing. The stallion didn’t have a leg to stand on given the situation, done up like a cheap whore with a pool of jizz leaking from himself. He went to protest but Velvet cut him off, holding up a hoof and shaking her head.

“I don’t want to hear it,” she chided. “Just...go up to your room; I’ll be up shortly. Twi,” she continued, looking down at the filly, “be a dear and get yourself cleaned up would you.”

“Ok mom,” Twilight responded, trotting off towards the bathroom to shower off.

“I’m just so disappointed in you,” Velvet said, returning her attention to Shining Armor. “How could you take advantage of your little sister like that?”

“I’m...just gonna go out for a bit,” Nightlight interjected, slowly backpedalling towards the door.

“Fine,” Velvet coldly said, “and you,” she thrust a hoof in her son’s direction, “Room. Now!”

The four ponies parted ways, Twilight heading to the shower, Shining Armor slinking back to the guest room, and Night Light retreating off to who knows where. Velvet levitated their belongings from outside, bringing them up to her room and shaking her head at what she’d just witnessed.

Shining Armor’s head was reeling, the last thing he’d expected was to spend the entire weekend at the beck and call of his little sister. He’d found himself salivating at the thought of her salty sweet cum flowing down his throat or her bloated shaft filling his behind. They must’ve been horrified at the sight of him getting plowed like a mare in heat, dressed up like some hussy with his sister balls deep in his bottom. Closing his bedroom door behind him, he reached back, feeling his swollen and tender anus. Merciful Celestia, it was so loose now, yielding to his hoof as he pressed into it. Even after only two days it’d become so sensitive that his touch sent a tingle of pleasure through his body.

The stallion walked over to the bed but stopped halfway across the room, catching sight of himself in a vanity mirror that sat against the wall. The mascara, which Twilight had applied, had run down his cheeks, streaked by tears of ecstasy from earlier in the day. Most of the blush and lipstick were both still in place, although the lipstick could use some touching up since most of it had been smeared around his sister’s prick or been left as kiss marks on her weighty balls. He smiled weakly at himself, admiring how the skirt and leggings accentuated his plump derriere and slim physique. Were it not for his stallionhood he could probably pass for a mare.

He knew his mom was going to ream him out after having caught what he and his sister had been shamelessly doing in the living room. The stallion felt awful, more ashamed at the fact that Velvet had seemed disappointed rather than angry. Night Light had looked pretty shocked as well, more than likely having gone out to get a drink in an attempt to scrub the salacious scene from his memory. ‘Hey wait,’ Shining thought, remembering Twilight mentioning something about what their parents did while they presumed she was sleeping. Maybe she’d just caught them in the act and wanted to emulate them but that didn’t quite add up; Twilight was an exceptionally intelligent filly so the fact that she compared her shenaniganz with her brother to what their parents did in private was disconcerting to say the least.

“Shining,” the stallion heard his mother’s voice as the door creaked open.

“Mom I’m so sorry, one thing led to another and before I knew it Twilight had me wrapped around her hoof,” Shining Armor lamented, casting his eyes downward in shame.

“I don’t want to hear excuses little man,” Velvet tutted, circling the stallion. “I was so proud when you told me you’d started dating Cadance. My precious son courting such a beautiful young mare, but I was wrong wasn’t I?” she continued, stepping before him and raising his chin with a hoof.

“No, I really do love Cadance! And, besides, what business is that of yours anyways?” Shining protested angrily.

“Hmmmph. I recognized that look on your face when I walked in, it was unmistakable,” Velvet sighed. “The way your eyes were glazed over, your cock pitifully dribbling cum on the floor. You were loving every second that Twilight was breeding you, weren’t you?”

“I said I’m sorry alright! What more am I supposed to do? Just let me get cleaned up and I’ll head back to the academy first thing in the morning,” the stallion shot back, shaking his head and feeling genuinely awful for succumbing to his lustful urges.

“Sweetheart,” Velvet cooed, caressing his cheek gently, “I think you misunderstand. I’m not angry, far from it in fact. I’m just a bit surprised is all and, given the circumstances, I feel like this situation could be used to teach you and your sister a valuable lesson.”

Shining Armor looked up at his mother’s smiling face but movement between her legs drew his attention to a turgid grey rod of flesh sprouted from her nethers as it gently slapped against her belly. He was shocked, in all the years he’d spent at home, seeing his mother virtually every day, he hadn’t the slightest idea that she, of all ponies, was a dickmare. While her member wasn’t nearly as large as Twilight’s it was still impressive, perhaps a touch thicker than his own and a bit longer as well. He gulped before looking back to her face, unsure of how to process this epiphany or what she’d meant when she mentioned teaching him and Twilight a “lesson”.

“Oh don’t look so concerned,” Velvet said, attempting to calm the stallion, “you had to have wondered where Twilight got her gift from before. I’ve simply had a lifetime to practice hiding it and I certainly wasn’t going to obscenely strut about in front of my own children with it on display; but now that the cat’s out of the bag…” Her attention trailed off as she looked to the doorway leading out to the hall. “Honey, you can come in now,” Velvet called.

Sure enough Twilight came parading into Shining’s room, her schlong wagging beneath her in its nearly persistent state of arousal. “Yea mom?” she asked, although her eyes didn’t waver from her brother’s supple rump. “Oh!” she chirped in excitement, “Is it time for that lesson you promised?”

“Wait, what?” Shining looked between the two, sudden realization hitting him like a sack of bricks, “You planned all this?”

“Well, mom and I wanted to give you a little test,” Twilight replied smugly. “She thought that you wouldn’t be interested in my ahemrather gifted anatomy but I argued the contrary. I’d noticed how your attention would linger on stallions and dickmares nearly twice the length of time than it would on ordinary mares. It didn’t help your case that I’ve found toys in your room before you moved out,” she persisted, grinning triumphantly.

“You shouldn’t have been snooping in my room!” Shining blurted. “Besides, those were Cadance’s.”

“But who was she using them on,” Twilight asked, leaning uncomfortably close. “It sounded an awful lot like a stallion moaning helplessly on a few occasions, or am I wrong?”

Shining’s mouth flapped uselessly, unable to form a coherent retort for Twilight’s accusations. She wasn’t wrong and she knew she wasn’t wrong; as studious and meticulous as she’d been her entire life she had him nailed to a wall.

“Just admit it,” the filly pressed, “you like being fucked.”

“Twilight! Language!” Velvet scolded, glaring down at the filly.

“Sorry mom, I’m just excited,” Twilight said, looking down to her brother’s hardening dong, “and so is he from the looks of it. So can we start the lesson now?”

“Of course honey,” Velvet replied before turning to her son. “And you get on the bed missy.”

The stallion silently complied, his body on autopilot and mind overloaded by his mother’s revelation. Draping himself on the bed, with his hind quarters hanging off the side, he looked to Velvet, somewhat anxious for whatever she had planned for him. In truth he was more than a little excited although he was loath to admit it; the fact that his mother had referred to him as “missy” hadn’t helped the situation either.

“Now Twilight,” Velvet said, approaching Shining from behind, “there are several ways to handle a mare to maximize pleasure for yourself and your partner.” Running a hoof along Shining’s side and to his abdomen she continued, “There’s a really sensitive spot towards their belly that you can hit if you know what you’re doing, take note.” Stepping behind the stallion she lined up her member with his still loosened pucker, slowing driving it in and causing him to groan slightly. “Now, rutting them is all well and good but watch what happens when I do this,” she said, grabbing hold of Shining’s right hind leg and hefting it onto her shoulder while repositioning herself. The grey dickmare reared up, placing her forelegs on the bed while her son was impaled on her rod as he lay slightly on his side. Velvet thrust her hips forward, her new position causing the head of her cock to directly impact Shining’s tender prostate and making the stallion writhe in pleasure. “See, if you service them like this he won’t last long at all. Look, he’s already leaking,” Velvet chuckled, watching Shining’s stallionhood ooze precum onto the bed sheet.

Shining Armor was awash in euphoria as his mom expertly fucked him. Being rutted by Twilight was amazing but the experience and precision of the older mare was astounding. Her pace and the way she caressed his body while she pumped herself into him was absolutely sublime. All he could do was whimper whorishly as she ground herself against his prostate over and over.

“Care to give it a try honey?” Velvet said, slowing her motions to a crawl as she looked back at the enthusiastic filly.

“Yes please!” Twilight exclaimed, excitedly trotting over. Velvet disgorged herself from her son’s posterior, leaving him a panting mess, to allow Twilight her turn. Twilight assessed the situation, raising an eyebrow before turning to her mother, “I think I’m too short mom.”

“Oh dear, hang on a second,” Velvet remarked, noting that the filly’s diminutive stature may prove problematic. “Ok well here’s what we’ll do. Shining flip onto your back on the center of the bed with your head at its foot, just prop your butt up on a few pillows for your sister. The stallion weakly nodded and obeyed, crawling to the middle of the bed and onto his back while levitating a few pillows under his rump. Twilight eagerly hopped up on the bed herself, getting between the submissive stallion’s supple white thighs.

“I bet you’re ready for this monster,” the filly snickered, rubbing her titanic member against her brother’s much smaller package.

“Another fine lesson to segue into,” Velvet chirped. “Shining, if you want to cum you should politely ask your sister for it. After all, a mare isn’t much good unless they know how to properly beg are they?” she said with a grin, watching the siblings with an expectant smile.

“Please Twili, just do me already,” Shining mumbled, blushing despite himself and averting his gaze.

“Pfft. You can do better than that,” Twili scolded, tantalizingly prodding his slack asshole with the head of her prick.

“Please rut me, I need it,” the stallion pleaded, reaching down and spreading his thighs in a desperate attempt to entice his sister.

“Such a needy slut,” Twi hissed, ramming her hips forward and forcing her length into Shining’s abused hole.

With Shining’s ass propped up as it was, he could feel every vein along Twilight’s colossal shaft as it plumbed his depths. As small as the filly was his body rocked with each of her thrusts; her plump nuts slapping against his cushy white buttocks as she pummeled him. While propped up on the pillows Twi was able to directly assault his prostate just as his mother had mere moments ago although Twilight’s exceptionally large size magnified the blissful effects exponentially.

“My that is quite impressive,” Velvet murmured, noting the distinct impression of Twilight’s member deep within her son’s gut. “Shining, dear, I know you’re enjoying yourself but you’ve forgotten something,” she sighed, walking over to the stallion’s head as it limply hung over the foot of the bed.

He looked up just as Velvet mounted the bed over him, her meaty dong wetly slapping him across the muzzle in the process. Shining didn’t need to be told what to do as he opened his mouth and closed his eyes, hungrily awaiting the slick pony meat his mother was offering.

“Such a good mare, I didn’t even need to ask you first,” Velvet groaned as she slid her marecock into her son’s mouth and throat. “Always remember mmmph a proper mare makes sure every dick is clean before they’re done.”

Shining Armor was in heaven, spitroasted by his younger sister and mother like some wanton whore. The stallion gagged each time Velvet plunged herself into his gullet, the taste of precum mingling with the musky scent of her nuts each time they slapped against his nose. He greedily lavished her with his tongue, slurping thirstily on her length. The stallion’s mind was on the verge of breaking, his gullet and ass packed to the brim with marecock as his stallionhood waggled uselessly under their combined assault.

“You really are a perfect slut Shiny,” Twilight goaded, continuing to piston herself into the stallion. “Maybe when we’re done mom and I will get you all dolled up and take you out on the town. Heck maybe Celestia would even allow us to visit the Wonderbolts after a show so you could give them all a little stress relief.”

Twilight’s words struck him like a hammer. The thought of being paraded around as a mare, servicing stallions and dickmares alike, was amazing. His cock began to twitch and flare weakly, the prospect of being turning into a cumdumpster for the Wonderbolts pushing him closer to the edge.

“Seems ugh like our little Shiny would like that,” Velvet commented, continuing to work the stallion’s esophagus. “Once he’s been subjected to this enough I doubt he’d even want to use his stallionhood. Isn’t that right sweetheart? You just want to be bred like a good little mare, being used by any dick that’d fill your hungry holes wouldn’t you?”

The dirty talk did it, pushing Shining Armor over the edge as he imagined himself being used and filled with an unending line of eager shafts. His prick began squirting spunk over his belly and the obscene bulge imprinted within it; he cried and gasped around his mother’s shaft as he was struck by a mind shattering orgasm. His thoroughly used ass flexed and violently constricted around his sister’s rod as he came.

“Fffffffuck!” Twilight wailed, the sudden tightening of her brother’s ass causing her to peak. Even though the filly had already cum at least twice that day she began to deposit yet another seemingly endless load deep into Shining’s colon. The stallion’s belly slowly swelled from the seething tide of spunk filling his ass.

Velvet joined mere moments later, hilting herself in her son’s throat as she blew her load directly into his stomach. The two dickmares groaned and wheezed, emptying themselves into the poor stallion.

Shining Armor’s eyes rolled into the back of his head, the mix of pleasure and lack of oxygen pushing him to the brink of blacking out. He honestly thought he was going to die of pleasure, never having been able to imagine that a pony could experience such heights of ecstasy. Fortunately Velvet was cognizant of the fact that he did need to breathe. Slowly she removed her dick from his throat, allowing the stallion to gasp and cough as he drew air into his lungs. Twilight soon followed suit, pulling her gargantuan length from his thoroughly battered rear. The stallion felt hollow, literally and figuratively speaking, as he lay there panting heavily. He could feel the torrent of slick spunk draining from his gaping ass, running down his plump cheeks and to the bed. It was in this moment that he knew his place, what he was made for.

“Thanks for the lesson mom,” Twilight wheezed, trotting over to Velvet and giving her a little hug.

“I hope you both learned something today,” Velvet intoned, still reared up over Shining as he clumsily attempted to lick her shaft clean.

“W...Wh…” he mumbled, drunkenly looking between the two, his face plastered in smeared makeup and jizz.

“When do you get your next lesson?” Twilight said with a conniving grin, finishing his statement for him.

“Well that’s all up to him honey,” Velvet answered, before looking back down to the broken stallion. “When do you want to start?”