“Ow.”

“Shit! Are you okay?”

Carrot Top rubbed her jaw. “You've got a hell of an arm on ya', Derps.”

“Very funny. Seriously though, are you okay?”

“Yeah, I'm fine. Just sore. Seriously, what the fuck just happened?”

“Uh...” Carrot Top was frowning. That probably wasn't a good sign. Derpy blushed and looked down. Carrot Top followed suit.

And that was when she finally saw it.

Her eyes widened and her jaw dropped.

“Damn, son.”

“... What, that's it? That's your reaction? 'Damn, son?'”

“Derpy, hon, anything I could say would be an understatement. Like, holy shit, that thing's as big as you are!”

“It's not that big...”

“Sure fuckin' felt that big.” Carrot Top got up, rubbing her jaw once more. “So, uh, I'm guessin' this is why you wanted to wait?”

“Little bit, yeah.”

“Don't say 'little' in relation to that, Derps, 's dishonest.” She reached over and grabbed her bag, opening it and rummaging around. “Hold on a moment... Ah, here we go.” She pulled out a small box, the kind that usually contains bandages or-

“Condoms?”

“Yep. I mean, let's face it, you're not gonna be able to get your swimsuit on while the elephant trunk is in the mood for fun, and it looks like your underwear, uh, didn't exactly survive it coming out to play.” Carrot Top was right; Derpy had broken more than a few pairs of panties when she tried to take them off with a hardon. Eventually, she had learned that there was a very specific way they had to be removed to avoid breaking them, something Carrot Top was unaware of. Her underwear was thoroughly ruined. “Soooooo I figure that we're gonna have to take care of him one way or another, and I'm optin' for the fun way.”

“Carrot Top, even if you somehow had a condom that could fit me, which I sincerely doubt, there's no way that I'm fitting inside you. Like, I get that we should probably deal with this if I want to leave the changing room any time soon, but it'd just be more practical to -”

Carrot Top placed a finger over Derpy's mouth. “Pfffft, please. You've got a cock the size of a limb and you think I'm gonna pass up the chance to ride it like there's no tomorrow? 'sides,” she waved the box of condoms around. “This shit's magic. They fit any cock, and as an added bonus, lets any cock fit any vag. Nifty if you're a size queen but don't wanna get torn in half.”

“... Why would you even have those?”

“You know me, always prepared for any sexy eventuality. Ooooh, they come in colours. You want blue or green?”

Derpy frowned. “No, seriously, why would you have magic condoms. Those can't possibly be cheap, and I really don't believe you can just walk to the convenience store and ask the clerk for a box of magic condoms. You'd have to order them from the internet or go to a specialty shop or something.”

Carrot Top sighed, tearing open a pale pink packet. “Look, Derpy, I know what you're thinking, and if I knew about your monster dong, do you really think I woulda gotten kay-ohed just then?” Derpy opened her mouth, and then closed it again. That was a very good point. “Not to say there ain't a story behind 'em, mind. Couple of years back, I caught AJ's brother, you know him? Big red guy, doesn't talk much. I caught him starin' at my tits, one thing led to another, and, well, let's just say that they don't call him 'Big' Macintosh for nothing.” She gave Derpy a meaningful look, and then suddenly her hand shot out and grabbed Derpy's penis, eliciting a surprised squeak from the mare.

“Carrot Top, what the fuck?!”

“Hush, hon, I just want a visual aid.” She grabbed the broad, flat head, while her other hand grasped the shaft at its base. “You've got him beat in terms of length, and your balls are bigger, too,” her lower hand moved to Derpy's testicles at this, lightly massaging them. Derpy tried her hardest to hold back a deep, guttural moan, if only to avoid interrupting the story. “But he wins thickness by a goddamn mile. When he got fully hard, I swear he was a fucking foot across.” She gestured, an act which ended her ministrations. This time Derpy couldn't hold back the pitiful groan at the sudden lack of attention.

Carrot Top grinned wickedly. The story was just getting started.

“All I know is that he couldn't get his hands all the way around it, and he's got some pretty big fucking hands, mind.” Carrot Top took a step back, taking in the sight of her squirming marefriend. She put on the sultriest smirk she could manage, and rolled her wide hips enticingly as she undid her belt and slowly pulled down her pants. Her panties were soaked to the point of being translucent. “So there we were, naked, horny, and he's got this monster cock and I want that shit in me. He's not gonna object, so I get ready to fuck him and it won't fit.” Top punctuated this by giving Derpy a light poke in the centre of her chest, sending her flopping down onto her butt. “Like, it's so huge that it just straight-up won't go in.” Top knelt in front of Derpy, all of her attention focused on her friend's lightly throbbing length. She leaned in close and gave it a kiss on the head, causing Derpy to spasm slightly. “And then he says that normally he's got these enchanted condoms for this kinda thing,” she waved the condom that she had removed from its packaging moments earlier to emphasize the point, “but he's only got the ones that fit him, not the ones that let him fit any ladies and I'm like, fucking excuse me? That's your excuse? How many ladies are you fucking that magic condoms are in short supply? And he gets all apologetic, but I ain't havin' any of that shit. I came here to get proper laid, not to give some guy a bj because his giant-ass meatstick can't fit in a normal-sized lady's pussy.” She gave Derpy another quick lick. “'course, I ain't adverse to a good blowjob every now and then, but it's the principal of the matter. So I storm off and leave him with blue balls and I've made sure to have these babies on me at all times ever since.” She deftly slipped the pink condom onto Derpy's cock in one fluid motion. “'Cause you never know when you'll have a cock emergency.”

Derpy had by this point been reduced to a quivering mess by Top's teasing. “Fuuuuuuuuuuck!”

“In a second, hon, gotta take off the panties first.” Carrot Top hooked her thumbs into either side of her last remaining clothing. She slowly pulled them down, rocking her hips back and forth all the way. The motion caused her pendulous breasts to jiggle ever so slightly, which drew Derpy's attention to them, and to the fact that there was still a very slight trickle of milk dribbling from her nipples. “Don't feel too bad if you come right away because it's not like I ain't already gotten my own orgasm outta this.” She finished removing her panties, twirling them around her index finger before deftly slingshotting them directly at Derpy's face. They landed on her snout, giving her a powerful nose-full of Carrot Top's sexual odours. Her mind was once again spinning with desire and arousal beyond conscious thought. “'sides, if I'd gone through alla' this teasing, I know I'd blow my proverbial load at the slightest touch, let alone a hot mare takin' me to the hilt. Speaking of which...” Carrot Top gently grasped Derpy's shaft with one hand, the other spreading her moist cunt. She licked her lips as she carefully guided the one to the other.

Derpy's vision blurred, her eyes rolling back into her head from the sheer sensory overload. True to her word, Carrot Top took all of Derpy in one fell swoop; in reality, it only took a few seconds, but it felt like an agonizing eternity. The sensation was like nothing Derpy had ever felt before. Heat and pressure, her massive length slowly being enveloped in the slick embrace of Carrot Top's tight passage. And it was moving, greedily pumping her cock for all it was worth. Even with the layer of enchanted latex acting as a buffer, the sensation was completely overwhelming. Derpy felt a tight warmth in her chest that rapidly moved down her abdomen, settling just behind her groin, somewhere between her cock and balls. She was dimly aware of her wings, fully extended and spasming wildly; of the lazy thrusting of her hips as she tried to get more of that wonderful warmth and tightness; of her hands grabbing Carrot Top's ample hips, fingers sinking into the soft flesh of her new lover's flanks. Her nose was overwhelmed by the musky, slightly tangy odour of Carrot Top's panties, still balanced on her face, a scent that only grew stronger with every thrust into Top's sex.

Carrot Top's breath came in shallow spurts in time with Derpy's thrusting. Her face bore a dopey grin like something from a really bad porno, her tongue lolling out. She knew she probably looked stupid, but she didn't really care - it just felt so fucking good. She'd never before had a chance to use her magic condoms, so she hadn't been sure exactly what to expect, but the result blew all her expectations out of the fucking water and into the motherfuckin' exosphere. She could feel every single square inch of the massive horsecock plumbing her depths as though she had the two-and-a-half feet of depths she'd need for it to plumb all the way. She was being stretched beyond her limits without actually being stretched beyond her limits. All of the pleasure, none of the nasty side effects of taking a cock the size of your arm, like the mother of all size queen's wet dreams came true all at once and she got to experience it firsthand. Every nook, cranny, crevice and contour of her tight passage was filled with cock all at once, and there was still more cock inside her, throbbing in time with Derpy's heartbeat. Each pulse sent a tingle down her spine. Her whole body, especially her pussy and her tits, felt like it was on fire. But, like, in a good way. A good kind of on fire, if that was even possible.

Fuck it, Carrot Top had never been good with words, and she had bigger concerns on her mind at the moment than describing the indescribable pleasure she felt. For instance, besides the rather blatantly obvious concern, there was the steady flow of moisture down her chest. Her breasts felt tight, a deep but insistent pressure pushing and stretching them from the inside. And it wasn't the fun kind of pressure, either; it was steadily getting more and more uncomfortable. This had happened to her occasionally, when the arousal-induced lactation wasn't enough to outweigh the milk production. Not unlike a cow (a comparison that Carrot Top's younger sister had made more than once, shit-eating grin on her face all the while. Top had taught her well.) And, not unlike a cow, there was a simple solution.

“Hey, Derps,” she said in between breaths. “Gonna need ya' to suck my tits. Like, now.” Derpy responded with an incoherent grunt, eyes still rolled back into her head, and her own tongue lolling out as well. “I'll take that as a 'yes.'” She grabbed Derpy's head, forcefully pulling her up from cowgirl to pounding on the spot before inertia took over and turned it into missionary, giving Derpy a face full of tit that she was more than content to enjoy herself with. The flow of sweet, rich cream was much more intense than it had been earlier, less a trickle and more a steady gushing of breast milk. Derpy's hands moved from Top's ass up to her neck, providing herself with better leverage to suck and thrust from their reversed positions. Carrot Top responded by wrapping her legs tightly around Derpy's waist, squeezing and forcing her deeper.

“Come on, Derps. Fuckin' come already. I wanna feel what it's like to get pumped fuller than full.” Derpy groaned, deep and guttural and muffled by Carrot Top's bosom. Top grinned. “Think of it. Gallons - no, more'n gallons. So much spooge it could fill a room, and all of it goin' into me. I want you to pump me so fuckin' full that it hurts, even with the condom. Fill me up so much that I look preggers. Nine months. With twins.”

Derpy couldn't help but picture it; Carrot Top so swollen with Derpy's seed that she couldn't fit through the exit of the changing room. That was what pushed her over the edge. She screamed, shoving her face deeper into Top's breast, as her balls pulled in tightly to her body and her cock convulsed before unleashing a torrent of semen. The flow was somehow stronger, more intense, and far more copious than her earlier session in the shower, like someone had stuck an industrial grade hose to her crotch and turned it to full blast. Gallon after gallon after agonizing gallon spewed out in an explosion of mind-numbing pleasure and every drop went into Carrot Top (thanks in no small part to the magic condom.)

And Carrot Top felt every drop pumping into her. She took back everything she had said about merely being filled with nearly three feet of horsecock, because being filled with three feet of copiously orgasming horsecock was ten thousand times more intense in every way imaginable. Every part of her felt unbelievably, unimaginably full, from her toes to her fingers to the goddamn hair on her head. She came again, and again and again and again, each orgasm more intense than the last. Her pussy convulsed wildly around Derpy's dick, spewing sexual lubricant that mingled with her milk and the results Derpy's own female orgasm.

And then Derpy came again.

Carrot Top's eyes shot wide open as Derpy's flow somehow intensified. “What the fuck, did you just come again without even finishing the first orgasm?” is what she tried to say, but all that came out was incoherent babbling with a few “fucks” and “more” and the occasional “celestia” thrown in for good measure. It shouldn't have been possible. Guys don't have multiple orgasms the way ladies do. But then again, Top mused through the haze, Derpy wasn't exactly a guy.

What followed was what felt like an infinite feedback loop of sex. Whenver one partner came, it pushed the other one over the edge into her own next orgasm, back and forth for what felt like hours but was closer to twenty minutes, only stopping when neither mare had the energy to continue. Derpy flopped over, rolling off of Carrot Top and pulling her finally flaccid cock out in the process, along with the condom. Considering how much fluids Derpy had punped into the thing, it should by all rights have inflated to the point where it filled the room, but the magic meant that the tip had only swollen slightly larger than one of Carrot Top's breasts.

Derpy wasn't sure if she was pleased with the life choices that led to her describing Top's tits as “only,” but when she rolled over and looked into her marefriend's eyes, she decided that it was worth it.

“We should probably get dressed.”

“C'mon, lemme bask in the afterglow at least a bit.”

“Someone might wanna use the changing rooms. 'sides,” Derpy slowly pushed herself into a sitting position. “We've only got so many hours to enjoy our beach vacation.”

“Fine, mom.”

The two mares cleaned up as best they could with the meagre facilities the changing room offered. There was a shower that didn't have nearly enough water pressure, and they took turns washing off what sexual fluids they could before changing into their swimsuits.

“You know, I should buy you some nicer swimwear.”

“I like what I've got.”

“It's a mom bikini, Derps. You're maybe half a step above frumpy one-piece.”

“So? In case you forgot, I am a mom.”

“Yeah, but if you're gonna be my arm candy, you're gonna have to step your game up a bit.”

Derpy rolled her eyes and adjusted the straps of her bikini. “If anyone here is going to be arm candy, it's not gonna be me, Top. Now come on, let's get goin'.” She turned and opened the door to the stall, behind which stood a very embarrassed Fluttershy and a thoroughly unimpressed Rarity.

“Thirty five minutes,” Rarity said, before Derpy could ask how long she'd been there.

“... oh.”

Each word came out slowly and deliberately through tight, irritated lips. “I am not going to begrudge you having sex on the beach, but I would appreciate it if next time you had the common courtesy to keep it in your fucking pants when you're occupying the only available stall in the changing room.”

Author's Note

wow, this took forever, didn't it? Well, if you're reading this, it's finally fuckin' done, after more than four months of technical issues, employment getting in the way, a lack of inspiration, and the universe generally conspiring to keep me from writing anything. It's done. Hooray.
Pounding on the spot is, according to wikipedia, the correct name for the position that Top and Derpy briefly fuck in. I kind of wish it were a bit snappier, but them's the breaks.
Feel free to pretend that Rarity and Fluttershy initiated a sexy, sexy foursome after the ending, but I ain't writin' that. Tune in sometime in the (hopefully) not-too-distant future for the sequel, Dinky's Big Adventure, which will be dedicated to explaining how Sparkler can be older than Dinky if Derpy only ever gave birth/had sex with a guy once (no it won't the answer is that Sparkler is a foster kid.)