It was a bright, sunny, Saturday morning, on Manehatten’s most popular beach. Stallions and mares lounged, enjoying the sea breeze, while fillies and colts romped in the cool water of the shallows. It was, for all intents and purposes, the perfect day for a swim; which was one reason why Twilight and Rainbow Dash had decided to go out.

“Come on, Dash!” Twilight called, waving for her friend to follow. Clad in a two piece swimsuit, and sporting a pair of sunglasses, the young alicorn was ready for some rest and relaxation. Her bikini, while matching her top, held a suspiciously large bulge at her groin, as the fabric struggled to conceal the sizeable equipment hidden beneath. As excited as she was, her girlfriend was slightly less enthused, mostly because of the outfit Twilight had chosen for her.

Stepping out onto the sand, Dash blushed. Under normal circumstances, she wouldn’t have gone out in a latex tube top and matching boy shorts, but she knew it made Twilight happy. They’d been dating for quite a while, and the nerdy purple alicorn had a bad habit of showing off her sculpted physique. True, there was a certain pride to take in the lustful glances of stallions, although they sometimes made her uncomfortable.

That was her only complaint about Twilight. Well, maybe one of her only complaints. Beyond her girlfriend’s exhibitionistic tendencies, the alicorn would often rope her into all sorts of strange experiments. Trying different magical spells, potions, and all sorts of exotic sex toys or accessories. Why, she’d even worn a vibrating egg, stashed in her panties, around for a whole afternoon once!

Still, Dash loved Twilight, and she always found herself forgiving the scholarly princess. Creeping onto the beach, Dash scampered to her lover’s side. Hungry looks or not, being near Twilight tended to calm her nerves, especially while wearing anything skimpy.

“Did I really have to wear this?” Dash groaned, glancing down at the form-fitting material of her shorts. They really didn’t leave much to the imagination, showing off the contour of her tush, as well as a prominent camel toe.

Looking her girlfriend up and down, Twilight shrugged. “Why not? I mean, you’ve always had a killer body; so why shouldn’t you flaunt it?”

Slim and athletic, Twilight had always been fond of Dash’s looks. She took great joy in getting the Wonderbolt flustered, which wasn’t hard. While she could routinely perform aerial acrobatics for the masses, being seen in public, while wearing anything which showed off a little skin, tended to get her blushing quickly.

“Look, I already picked a spot out for us,” Twilight announced, pointing to an umbrella on a nearby dune. Grabbing her lover by the hand, she guided Dash to the location she’d chosen.

A large beach umbrella was set up, shading a pair of oversized towels. A small cooler sat to the side, filled with ice and a few beverages. Lastly, a satchel of various beach related goods was deposited at the base of the umbrella. It wasn’t an extravagant sort of date, but the two preferred their time together to be quaint; well, outside of the bedroom anyways.

Dash shielded her eyes, as she seated herself on one of the towels. Sitting as she was, her face was just under waist level, she peered over to Twilight’s crotch. When they’d first met, she’d had no idea that the reserved alicorn, a unicorn at the time, had been a dickmare, but she certainly wasn’t complaining now. As their friendship blossomed into a relationship, and the truth came out, Dash had been elated. She’d never really been into stallions; but a mare with a cock? Yeah, that’s a concept she could get behind, or under.

Rummaging around in the bag, Twilight produced a bottle of suntan lotion, before turning to her partner. Uncapped the bottle, she squirted a generous portion into her palm. As she rubbed the thick cream between her hands, a wry grin crept across her face.

“Alright, Dash, are you almost ready for some fun in the sun?” Twilight chuckled, working the thick substance between her hands. Of course, she didn’t want Dash to get sunburn, although there was a slightly more nefarious scheme unfolding.

Over the last few days, Twilight had been perfecting a very special sort of suntan lotion. Along with its UV blocking properties, it magically and hormonally enhanced a female wearer. Not only would whoever used it be infuriatingly alluring to stallions and dickmares, but they’d also get rather turned on themselves. The way she saw it, it would be fun to get Dash and herself all worked up, before heading back to their hotel room to fuck like rabbits. A simple plan, but an entertaining one nonetheless.

Looking up, Dash nodded, while she presented her back to Twilight. Embarrassed or not, she didn’t want to leave the beach overcooked. A contented sigh escaped her, as her partner started to gently massage the lotion over her shoulders. Just as she was starting to relax, she felt a hand slip under her top.

“Gotta get the front too, Silly,” Twilight softly giggled, rubbing the pegasus’ breasts and upper chest. While Dash didn’t have the biggest rack, a sporty B cup, they were rather perky and rather fun to play with. Her own bosoms weren’t much larger, something she took a certain pride in, although she didn’t mind her partner’s tits in the slightest. Still, she wasn’t going to let the chance to cop a feel slip through her fingers.

Finishing with Dash’s torso, Twilight stood and tossed the bottle back in the sack. Reaching down, she pulled her friend up, before squatting down before her. Rubbing the final bits of sunscreen on Dash’s thighs, she took a moment to appreciate the sight. The girl’s cameltoe, plump and inviting, hovered a few inches from her snout, concealed behind the latex boyshorts. Yeah, she couldn’t wait to rip those puppies off, but that could come later. After all, if they’d just wanted to bang one out, they could’ve stayed in the hotel room all day.

“So are we gonna swim now, or are you going to look at my crotch all afternoon…” Dash grumbled, keenly aware of what Twilight was looking at. Honestly, it didn’t really bother her, although coming to the beach had been Twi’s idea.

“Right, sorry,” Twi murmured, standing and taking Dash’s hand. Leading her to the surf, the cool water splashed over their feet. While Twilight stifled a squeak of surprise, Dash cursed under her breath, the temperature difference hitting each of them at the same time. Slowly, they edged deeper and deeper, acclimating to the chilly sea, until the two were submerged to their waists.

A playful splash from Dash, nearly causing Twilight to scream, kicked off their aquatic activities. The two romped, throwing water at one another, while laughing in the sun. Eventually, after the initial skirmish, they began to relax. Due to how calm the waves were, Dash opted to simply float on her back, enjoying the warm rays, while Twilight swam about, using her wings for additional speed and power.

Feeling something bump against her toe, Twilight dove down to the sandy bottom. Although she couldn’t see all that well, she plucked the offending object up, before surfacing. It was a bright pink sea shell, with off colored tracings on it. Pleased with her find, she looked about for Rainbow Dash, so she could show it off.

Fortunately, it only took her a second to find the bobbing blue mare, since she was only about thirty feet away. Paddling over, her movements slowed, when she realized Dash had her eyes closed. The water was still quite shallow, only coming up to her chest, so she had a number of options. Smiling to herself, she stealthily approached her prey.

As Dash floated on her back, nearly drifting off to sleep, she felt something hot against her ear. It wasn’t the breeze, since it was way too warm. Before she could crack an eye open, something flew down the back of her shorts, firmly grasping one buttock. In a panic, she shouted; thrashing about, while she tried to stand. Finally, after a very soggy struggle, she turned, only to find Twilight.

“T...That’s not funny!” Dash pouted, crossing her arms and turning her back.

“Oh, come on. It’s not like you haven’t done worse!” Twilight retorted. “Or did you forget about the time I woke up with my dick in your mouth…”

“S...shut up!” Dash protested, wheeling around angrily. She could already feeling her face turn beet red, and it wasn’t from the sun. True, she had helped herself to Twilight’s dong one morning, but that was only because it was already flopped out. Before she could say anything else, the purple alicorn walked closer, only stopping when her arms were wrapped around her.

“Or what about the time we did it in Celestia’s castle…” Twilight cooed into Dash’s ear; giving it a small lick, for added effect. She couldn’t tell if it was the magical potion or not, but she could sense her loins stirring. Breaking taboos was hot, especially when there was a chance of getting caught.

“I…” Dash’s complaint died, as she felt something hot pressing against her abdomen. Glancing down, through the crystal clear water, she spied a violet length of flesh, peeking out from the top of Twilight’s bikini. She couldn’t help but be a bit turned on at the sight, especially since she was the cause of the Princess’ erection.

Shaking her head, Dash tried to gather her thoughts. She shouldn’t be getting this worked up over seeing Twilight’s cock. For fuck’s sake, she’d looked at it more times than she could count; so why was this time any different? She felt fine, other than a slight ache in her marehood, so she doubted she was ill, but she didn’t know what had come over her.

Peering down at the meaty organ, and sensing her pulse quicken, something else started moving. A second tool, identical to the first, snuck out of Twilight’s bikini. Now looking at a pair of dicks, she doubletaked between her partner’s groin and face. It wasn’t until Twilight, with an impish look in her eye, tapped her horn, that she knew what had happened.

“Seriously? You seriously just gave yourself another cock?” Dash hissed, trying her best to look angry. While they’d used magic in the bedroom before, she’d never done anything with body altering sorcery. At most, they’d employed toys and accessories; oh, and screwing with a levitation spell on one occasion.

“Why not?” Twilight purred. Elegantly, she circled around Dash, before pressing her breasts to the girl’s back. “Why shouldn’t I toy with my little blue bolt on the beach?” she teased. Her hand glided over Dash’s hip, under her shorts, and to her marehood. Her cocks, each steadily growing rigid, ground against her partner’s ass. Taking a breath through her nose, a tingle went through Twilight’s spine. Yeah, that special lotion was definitely having an effect.

Normally, she’d have restrained herself to getting a little handsy; yet here she was, fingers teasing Dash’s cunt. Not only was she sporting a pair of rapidly hardening dongs, but she was starting to have a hard time thinking straight. The world felt fuzzy and warm, her body was hot, and everything seemed out of focus. The one thing, the single locus she could fixate on, was Dash.

Breathing hotly into the Dash’s ear, Twilight slid one finger into her partner’s snatch, quickly followed by a second. “Tell me you want it…” she breathed, feeling the girl’s silken folds around her digits.

“I...I…” Dash murmured, unsure of what to say. What had gotten into her? Any other time, if Twilight had tried something this audacious, she would have protested. Hell, she’d even slapped the Princess once, when she’d tried to finger her at a party. Now, she couldn’t care less. Her mind kept wandering back to Twilight’s cocks, no matter what she tried; their contours, how thick they were, how good they’d feel buried inside of her, they were just perfect. A ragged breath escaped her, as she felt them pressing against her ass.

“Do it,” Dash whispered, reaching back and pulling the cheeks of her tush apart. They were deep enough in the water that it would be hard for anyone to see them. That, and the beach wasn’t especially crowded.

Upon hearing the shameless request, Twilight leapt into action. Squatting down just a bit, she grabbed both of her tools; holding them together, she guided them to the crevice at the very bottom of Dash’s ass. Removing her fingers from the girl’s cunt, yet keeping her hand in place, she freed the canal, for her meaty delivery. As many times as they’d fucked, she had damn near marksman-like precision with penetrating the Wonderbolt. Sensing the warmth of her lover’s entrance, Twilight rammed her hips forward.

Clamping a hand over her mouth, Dash barely stifled a gasp. In her fervor, Twilight had penetrated her through the latex shorts; effectively causing the garment to become a makeshift condom. Each dick was as big as Twilight’s normal tool, meaning she currently had double the girth crammed within her marehood. It was odd, she would have thought it would hurt, or at least be uncomfortable, yet it felt amazing.

Rocking her hips back, and regaining a bit of composure, Dash reached behind herself. Running her fingers through Twilight’s mane, she looked over her shoulder. “You can start anytime now, Stud,” she hissed.

A predatory grin appeared on Twilight’s face. “If you say so,” she responded, slowly retracting her hips, before plunging them forward. Blissfully unaware of the wardrobe malfunction, due to the new sensation of having twin cocks, she steadily humped away. Gradually, she found her rhythm, as the two embraced.

From an onlooker’s perspective, the scene didn’t look that out of place. Two mares, one hugging the other’s back, stood in the chest deep water. They appeared to be talking, likely chatting about whatever mundane subject young woman did at that age, while enjoying the relaxing ocean waves.

“Oh Fuck, they’re so big!” Dash croaked, flexing around Twilight’s cocks. Clenching down on them, while pushing back against her lover’s thrusts, she did what she could to reciprocate.

“You - Mmmph - want ‘em bigger?” Twilight blurted, shamelessly sliding a hand under Dash’s top, to tweak and tease the girl’s nipple.

“Mmmhmm,” Dash hummed, biting her lip.

“How much bigger?” Twilight shot back. Pulling the girl’s top up, her breast’s bobbed free, while she continued to toy with them.

“So big. As big as you possibly can,” Dash wheezed, groping her free bosom.

Thought neither of them were aware of it, the altered suntan lotion had worked a bit too effectively. Neither Twilight nor Dash were able to concentrate on anything but one another, or the carnal bliss each could afford. Admittedly, the Princess had taken measures to ensure the concoction’s potency; going so far as to use a number of alchemical and sorcerous enhancements. Regardless, the stuff worked, and there was little either of them could do to change it.

Twilight’s horn ignited, surrounding Dash in an aura of lavender energy. Some part of her brain realized she had to take precautions, to ensure her friend wasn’t injured by what she was about to do. There was a spell she’d learned, some time ago; a spell which could, supposedly, double or triple one’s size. Was it made with sexual endeavors in mind? Of course not. But, for her lust crazed mind, it was as good of a time as any to try it. But first, she had to tend to her lover.

Noticing herself being covered by soft, purple light, Dash groaned. While the dual tools pistoning her abused cunt felt great, whatever spellcraft Twilight was evoking added something special to the sensation. It didn’t hurt or anything; far from it, in fact. Her entire body felt tingly and energized, almost like she was electrified. The only unfortunate side-effect was that the fucking lost some of its intensity; at least, that’s what it seemed like.

“W...Mmnn...What did you just do?” Dash asked, glancing back at her lover. She wasn’t complaining, simply curious about what sort of magic had just been cast.

Twilight was too focused to reply, as the light around her horn nearly doubled. Altering Dash had been the easy part, since it was just a passive spell. The second part of her plan, however, was going to take a lot more concentration. Gritting her teeth, yet continuing to plow the blue pegasus in front of her, she sluggishly rose out of the water. It wasn’t that she was levitating, or fly; no, she was growing.

Every part of Twilight Sparkle was expanding, ponderously increasing in size, as she held Dash to herself. The framework of the spell was tricky, to say the least. Expand one portion too fast, or at a different rate than the others, and she could end up hurting herself. Thankfully, being the prodigal protege of Princess Celestia herself, she was able to pull it off; all it required was a bit of concentration.

Considering she was being rutted, it took Dash a moment to realize something was off. Her perspective seemed strange, and the intensity of the dual members pistoning her marehood slowly started to return. It wasn’t until she opened her eyes, paying careful attention to Twilight’s hand on her hip, that she put the pieces together.

“A...are you getting bigger?” she blurted, fearfully looking back to her friend. As it stood, they only had a few inches of water above their waists, before the entire beach got a view of what they were doing.

Nodding, Twilight moved one hand from Dash’s hip to her abdomen. Patiently, she waited, while she kept rhythmically fucking the girl, until she sensed something bump against her palm. She knew it was only a matter of time until her expanding anatomy had a visible effect on Dash, and she wanted to relish her partner’s reaction to it.

Reaching down, she grabbed Dash’s hand, still excitedly rubbing her clit, and guided it to her belly. “You feel that,” she whispered, giving a few exceptionally hard thrusts, to ensure her cocks would bulge her stomach.

Feeling something grinding against her hand, Dash looked down. Be damned if there wasn’t the imprint of Twi’s equipment from inside her abdomen. Flabbergasted, she watched it appear and disappear, with every stroke her partner took. Not only was it a captivating sight, but it felt absolutely amazing. She realized it should probably hurt, or at least be uncomfortable, but the only sensation assaulting her was pleasure.

“You want more?” Twilight purred, locking hand over Dash’s own. She was already several inches taller than her partner, but their difference in size was rather striking. Looking up and back, with a desperate look in her eye, the pegasus nodded.

“You want everyone to see me fucking you?” Twilight continued, her wolfish smile returning.

Again, Dash nodded, possibly more enthusiastically than before. The excitement, coupled with the lotion’s effects, where overriding the higher functioning portions of her brain. Timidity crumbled under bliss, humility was utterly quashed beneath the sinful delights of magically augmented rapture. People would soon see her being used, but she didn’t care; just so long as Twilight didn’t stop.

She could feel her insides rearranging, shifting about, as they accommodated her partner’s titanic equipment. To Hell with the consequences! If her options lie between stopping the profound ecstasy she was experiencing, growing stronger by the second, and putting on some shameless, exhibitionistic display, she’d choose the latter.

Great gouts of pre-cum flooded her insides, adding tension to the struggling pair of shorts entombed within her womb. The rubber of the garment ballooned outward, expanding beyond anything it was meant to bear. Unable to cope with the influx of fluids, nor the mammoth cock battering it, the rubber exploded, bathing Dash’s interior with Twilight’s slick fluids.

Dash shuddered, sensing the miniature detonation within her womb. She jerked in place, mewling in bliss, while her insides were painted with yet more of Twilight’s juices. Strings of the sticky stuff leaked out of her hole, snaking down the pair of cocks pistoning into her. Sweet Celestia, if she hadn’t been wet enough before, she sure as hell was now.

Pleased with Dash’s reaction, Twilight pumped more power into her spell. This was only the appetizer, the main course had yet to come. In the blink of an eye, the speed of her growth nearly doubled. Locking her hands over her partner’s midsection, she held the girl in place. Inexorably, she rose of of the water, while she fucked away.

Dash’s eyes rolled to the back of her head, as her body was rocked by an orgasm. The jump in Twilight’s size had forced her, quite literally, to cum. There was no buildup, no gradual escalation, simply a explosion of ecstasy. Her arms and legs went limp, hanging uselessly, as nectar feebly squirted around the pair of cocks plumbing her marehood. It almost felt like she was floating.

Dreamily, Dash looked about, only to notice she was floating, in a sense. Twilight had, at some point, begun to fully support her weight, holding her by the waist, as they fucked. She was roughly the size of a small child, standing to her gigantic partner’s thigh, if she had to guess. For buck’s sake, it took every ounce of concentration she had to figure that out, so overwhelming were the physical sensations of being fucked by someone so much larger than herself!

“Bigger,” Twilight groaned, dumping more power into her magic. In short order, she was large enough to easily hold Dash in one hand. Effectively using the girl like a living masturbatory sex toy, Twilight unabashedly got herself off. Her free hand moved to her bosom, kneading and massaging the massive tit, while occasionally twisting her nipple.

The beach-goers watched, in a mix of awe, horror, and outright voyeuristic delight, as the titanic alicorn pleasured herself with the seemingly miniature pegasus. Several families fled, mostly ones with young children, while other individuals stayed to appreciate the spectacle. A few stallions and mares openly pleasured themselves, finding the bizarre sight too much to bear. Regardless, it was a show unlike any other.

With Twilight’s gargantuan digits wrapped around her body, now pinning her arms and wings to her torso, Dash was helpless. Every part of her, from her organs to her very bones, warped and contorted, while she was used. If there was any pain, she was unaware of it. Her existence, every fiber of her being, was engulfed with pleasure; surrendering herself to it, her mind went blank. One orgasm bled into another, leaving her a drooling, gibbering mess.

Waves crashed around the Princess’ ankles, as she fucked her toy. The air was filled with her debased, throaty grunts, while she unabashedly pleasured herself. It was a wonder to behold; an alicorn, towering nearly fifty feet tall, plowing a much smaller, much stretchier, pegasus. If such a thing had happened in Equestria’s past, none could remember it, save for possibly Princess Celestia or the Pillars of old.

Gritting her teeth, Twilight continued. The dual cocks, each nearly as large as Dash herself, plumped the girl and distorted her frame. The spunky Wonderbolt was little more than an onahole, albeit one that could appreciate the joy of servicing an enormous alicorn. She knew the girl would be fine, that no harm would befall her, so she had no hesitation to give her everything she had.

Pumping her hips, and stroking herself with Dash, Twilight’s balls began to retract. Try as she might, she could only stave off her impending orgasm for so long. Between the excruciating snugness of her partner, and the sensory input of two cocks, she wasn’t able to hold out. With one final, tectonic plunge, she buried herself in her partner, stretching the small pegasus to the max.

Barrelfuls of cum rocketed up Twilight’s tools, causing them to obscenely pulsate, as the massive dickmare unloaded into her mate. With the inexorable force of a tsunami, Dash’s body began to swell and deform. Her frame ballooned outward, under the influx of dozens of gallons of seed. For all intents and purposes, she was a living condom; a sorcerously augmented pony who’s sole use, in that moment, was as a receptacle for her lover’s spunk.

The heat, coupled with the sublime pressure of being filled, caused Dash’s mind to fracture. It couldn’t be called an orgasm; no, that was far too much of an understatement. The ecstasy she felt was beyond compare; so much so that it would be likened to an existential shift in thought. Unaware of her form warping, or just how swollen she was rapidly becoming, her entire existence was nothing but rapture.

Somehow, someway, Twilight’s cocks shifted, each moving slightly within Dash. Veering off to either side, they hammered against the pegasus’ fallopian tubes, the very entryways to the girl’s ovaries. A forceful thrust, combined with her partner’s pliable body, allowed the unbelievable to happen. Each shaft plowed against, and into, the tubules; effectively violating their way directly to Dash’s egg factories.

Seed erupted through the pipelines; miniature tidal waves of cream coursing to her ovaries. Dash writhed uselessly, squirming in Twilight’s grip, as billions upon billions of sperm filled her. Although that part of her was never meant to be graced by another, the sensation was heavenly. Of its own volition, due only to the magical lotion and Twilight’s sorcery, her body embraced the feeling, driving her mad with pleasure.

Vast gouts of jizz dribbled and squirted out of Dash’s confines, crashing down to the sea, while Twilight’s climax drew to a close. She couldn’t be sure if it was their difference in size, the dual lengths of dick she sported, the magical lotion, or some combination of the three, but the entire experience was beyond compare. Yeah, she’d definitely need to remember this trick for later.

Hauling her massively bloated partner off her tools, Twilight cupped the girl in her hands. She really did look like a cum-dumpster, both in size and in her contents. Still, she had a blissful look on her face, so she didn’t appear to mind her slick and swollen state.

“You...alright?” Twilight wheezed, the post coitus stupor overtaking her. Feebly, and rather dreamily, Dash nodded. “You want to go home?” she continued, realizing several hundred onlookers were eagerly watching. Again, the pegasus nodded.

Concentrating her magic, with a bit of mental effort, Twilight evoked her power. In a blinding flash, and rush of displaced air, the two disappeared. They were gone, just like that. The sea rushed in upon itself, at the massive mare’s absence. With the performance ended, the gathered ponies began to disperse, leaving the beach. With the nearly incomprehensible amount of cum in the water, it was understandable that perilously few were willing to continue their swim.

Re-appearing outside of Ponyville, well out of sight of the populace, Twilight stooped down. Gingerly lying Dash on a grassy knoll, she seated herself beside her mate. Expending more of her magical reserves, she steadily shrank herself, being mindful in undoing her spellcraft. Dash would be fine, once her body was drained from the small pool’s worth of cum.

“Good time?” Twilight asked, caressing her partner’s extraordinarily distended belly.

“Y...yeah,” Dash croaked, her faculties slowly returning. Like it or not, their romp had been eye opening. Sure, she’d rather not have made a scene of it, but she sure as hell wouldn’t mind doing it again, preferably in private.

Holding Dash’s hand, Twilight began to undo her magic, draining her mate and returning her body to normal. Only time would tell what sort of sexual adventures the future would hold for the two…