I was totally not okay.

But thank Celestia, I’d finally found Twilight Sparkle. She was working in one of her upstairs laboratories with the windows open, so I flew right in. “Hey, Twilight. Could I bug you for a second?” I tried to sound casual, but it wasn’t easy to keep my cool.

“Rainbow!” Twilight gasped, setting down the beaker full of glowing indigo liquid she’d been examining. “What’s the matter with you?”

“Nothing’s the matter,” I said, dancing lightly from my left hooves to my right and back again. “I just came by to chat. Why would you think anything’s the matter?”

Twilight sighed. “Well, first off, you’re wearing a dress. The one you wore to the Gala, actually. Is that the only one you have?”

It wasn’t the only one I had. But my Wonderbolts Reserves dress uniform was at the dry cleaner’s, and I was never going to get the stains out of the tight little red number I’d worn out last Saturday night. “Maybe I want to dress up a little now and then. It’s not a crime.”

“Uh huh. And you reek of perfume. Fluttershy’s perfume. And don’t tell me it’s from you two cuddling — she’d have to have been swimming in it for her to have gotten that much on you. Also, you’re doing a potty dance.”

I cringed. The burning between my legs was making it hard to concentrate. “Twi, can we please talk about this somewhere more private?”

Twilight rolled her eyes. “We’re alone in my castle, Rainbow. Spike is hanging out with the Crusaders today. We can talk here.”

“Twi, the acoustics in here are ridiculous.”

Twilight leaned towards my rump and squinted at the wrinkled fabric. Rarity’s magic had long ago worn out of it, and it lay heavy on my plot, making me look like a tank. Twilight stroked her chin with her hoof. “You have a venereal disease, don’t you?”

I collapsed into a puddle on the floor, and covered my eyes. “I don’t know. All I know is, something’s wrong back there.” I was not going to cry. I was way too awesome for that.

Twilight sighed. “You know I’m not a doctor, right?”

“But you’re smarter than any doctor. And if I go to the doctor I’ll have to be in a waiting room, and then I’ll have to go to the pharmacy, and everyone will know! My reputation will be ruined!”

Twilight snorted. “They’ll know you’re a sexually active young mare. These things happen. I just hope it isn’t anything serious. I do wish you’d be more careful.”

I raised my head. “But I was careful! I even made him wear a condom, for once!”

Twilight looked confused. “Really? Who were you with?”

I coughed into the inside of my foreleg. “Hgh Mlly.”

“What was that? I couldn’t hear you.”

I cringed. “Hugh Jelly.”

Twilight frowned. “Rainbow, if I’m going to help you, you’re going to have to be serious. Who did you have sex with?”

I curled up in a ball, and wrapped my forelegs over my head. “I seriously had sex with Hugh Jelly. We’d both had a few ciders, and I thought… you know, why not do it in a tub of jelly?”

Twilight started laughing, and didn’t stop. She rolled on the floor, hind legs kicking, wings flapping, front legs folded over her tummy.

I scowled. “Well, I’d never done it before,” I whined. “I wanted to know what it was like.”

“And what was it like?”

“Sticky.”

Twilight rolled over onto her front, and wiped a tear from her eye. “Rainbow, you know he doesn’t keep those tubs at anything like a safe temperature. They’re probably crawling with microbial life!”

“Only you’d know that, egghead.”

Twilight chuckled. “Being an egghead has its uses, you know. Come on, let’s get that dress off you and have a look.”

Twilight levitated a speculum, some swabs, and a tube of her special recipe animal birthing agent out of a nearby chest, while I shrugged out of my dress, turned around, and lifted my tail. I’d often wanted to lift my tail for my adorable, pudgy little nerd friend, but not like this.

“Woo whee! It’s like low tide threw up in there!” Twilight wrinkled up her nose, and turned her head away. “I can see why you were wearing so much perfume!”

“Twilight, please,” I whimpered, “can we just get this over with?”

“I’m sorry. Well, there’s certainly quite a bit of swelling. And some discharge. Just a second while I crank you open…”

I yelped, “Cold! Cold!”

“Sorry. Is there itching?”

“Yes!”

“Does it burn when you pee?”

“Yes!”

“Hmmmmm.”

“Are you done yet?”

“Honestly I have no idea what I’m looking for. It is interesting to see what you look like on the inside, though. I guess you’re very healthy. You know, aside from being bright beet red and dripping with green pus. Is that your cervix back there?”

“Twilight!”

“Just let me take a sample. I think I’m supposed to tell you you’ll feel a brief cramping sensation?”

“Ouch!”

Twilight took the sample, carefully withdrew the speculum, and levitated it over to one of the lab’s sinks.

“Is there anything you can do for me?” I asked, turning back around and tucking my tail protectively over myself. Twilight had put the speculum in a ceramic bin, and was pouring disinfectant over it.

“I don’t know, honestly. Let’s have a look-see,” Twilight said, fiddling with her microscope and some slides. “Looks fungal, I’d say,” she said after a while. “Okay. Right now I see a few choices.”

“Yeah? I’m desperate here, Twi.”

Twilight turned around to face me. “Option one. You go to a properly trained doctor, and get a cream or a suppository or something. You’ll probably be fine in a few days.”

I shook my head. “Not gonna happen.”

“I want to add before I go any further that number one is the best option. That is the one you should do.”

“Nope.”

“Okay, option two is that I attempt to magically burn away the infection. I can probably do it without seriously injuring you. If I’m careful.”

I pressed my hind legs together.

Twilight began to pace. She was working up to something she felt excited about. I really hoped it wasn’t her torching my vagina.

Twilight continued, “It will probably hurt. A lot. And take days to heal.”

I locked my knees against each other.

“Also there’s a chance — just the slightest chance, but definitely non-zero — that the process will sterilize you.”

I plopped my rump down on the floor. “Is there an option three? I’m really hoping there’s an option three.”

Twilight took a deep breath and levitated a thick book with an unmarked wooden cover down from a high shelf. “Yes. There is. I’ve been reading this old book on sex magic. It’s mainly about using sexual activity to channel the power of multiple unicorns into super-powerful spells. But…” Twilight began to flip through the pages.

I grimaced. “But? Don’t leave me hangin’, Twi.”

“There’s a section on preventative measures. Contraceptive spells, so that mares who are in heat can participate in the rituals. Prophylactic spells, to prevent the spread of venereal disease between participants. And, if those don’t work…” Twilight held the open book out towards me. The two page spread was covered in diagrams, magical symbols, complicated-looking instructions, and copious notes in Twilight’s illegible horn-writing. Most of the spread was dominated by a large magic circle that, in spite of being fairly simple in design, seemed to twist slightly in place. It made my head hurt to look at it.

I peered around the edge of the book at Twilight, who was grinning like an idiot and bouncing up and down on the tips of her hooves. “Twi, what am I looking at?”

“The most powerful curing spell I’ve ever seen! If it works the way it’s supposed to, this should cure any illness caused by an invasive organism! Not just venereal disease, but anything! From the common cold to ringworm to PIV!”

“Great!” I narrowed my eyes suspiciously. “So what’s the problem?”

Twilight slid a Daring Do and the Spear of Destiny promotional bookmark into the book, shut it, and set it aside. “Well, I don’t know if it actually works. I haven’t tried it yet. I’m skeptical that such a powerful healing spell wouldn’t be in general use, if it was really as effective as all that.”

“So I’d be your guinea pig.”

Twilight nodded. Her grin widened. “It’s a terrible idea, Rainbow,” she hissed between her teeth. “Don’t do it.” A vein under Twilight’s eye twitched.

I considered the potential consequences, but even nearly being cooked alive by Fluttershy’s animals again didn’t seem that bad, compared to losing my reputation for good health, vigor, and extreme sexual availability. “It’s a no-brainer, buddy. Let’s do this.”

———

In the year and a half since she had moved into the new palace, Twilight had arranged for certain renovations to be made. The basement as it had ‘grown’ had been a honeycomb of small chambers and twisting corridors, apparently meant for the storage of things no one ever needed to find again. Hyper-organized Twilight was having none of it, and had workponies come in and knock down all those walls and doors, leaving one huge, empty room about the same size as the throne room above. If long-term storage was needed, the palace had many other places to keep things, including a sub-basement and a sub-sub-basement.

Then she had stuffed it full of books, chests, and magical equipment, making it nearly as cluttered as it was before.

Twilight had copied the big circle from the book onto the center of the floor, and made me stand in it. Once I stepped inside, I began to get a feeling that the room was rocking slowly, like a boat in calm water. It made me nauseous.

Twilight taped some electrodes to my fur (not part of the spell, just for research purposes), then spent over half an hour staring at me, flipping through that big sex magic book, fiddling with the design of the magic circle, making notes on a pile of parchment, and muttering to herself. I sighed, and held my back knees together. This infection wasn’t doing anything for my bladder control. If Twilight didn’t get this spell done soon, then she was going to need to go get a mop.

“Twi, can I go take a piss?”

“No! You can’t move, or you’ll smudge the circle! Anyway, I think I’ve got it. Hold very still.” Twilight slammed the book shut, sucked in her gut, puffed out her chest, and spread her wings dramatically. Her horn began to glow purple, then white. A high-pitched metallic whine filled the room. Twilight’s eyes glowed with a fierce white light, and she began, very slowly, to rise off the floor. Then there was a sound like Bulk Biceps ripping a phone book in half, and things started to get really strange.

My perception of the room shifted — though my mane and tail remained perfectly still, the room seemed to be spinning around me like I’d stalled out and gone into a tailspin. A searing pain tore through my whole body, and I suddenly had the feeling of rapidly moving away from myself.

Then everything was back to normal. Twilight was grinning a big shit-eating grin at me, and my vagina didn’t hurt any more. “Did it work?” I asked, then froze. There was something wrong with my voice. What was wrong with my voice?

Twilight was upbeat, but her lower left eyelid was twitching again. “Oh, it sure fixed what was wrong with your vagina. Yep. In fact you may never have a problem with your vagina, ever again.”

I cleared my throat. “Do re me fa so la ti do. The quick brown fox jumped over the lazy dog. Lazy dog.” My voice was deep and slightly nasal, but gravelly. I sounded like Shining Armor with a sore throat. “Twilight, what have you done to me?”

Twilight seemed smaller. She raised her hooves placatingly up at me. “The important thing is to remain calm. Yes, we all need to be calm. Just take a deep breath. Lots of deep, deep breaths.” She began hyperventilating.

It wasn’t just Twilight. Everything seemed smaller, because I was bigger. And my vagina didn’t hurt, but it did feel really strange, like it was inside out, and in the wrong place. I flopped down on my plot, and leaned back, looking down my barrel. “Twilight, why do I have a dick?”

“Rainbow, I am so sorry. I am really, really, really sorry. I cannot even begin to tell you how sorry I am, because I am just that sorry.”

I remembered rumors I’d heard about how the Princesses liked to break out penis potions after particularly arduous policy meetings. Maybe this was like that, and little Dashie was nestled away safely behind those (rather dapper, if I did say so myself) dark blue balls. I reached down to shove them aside and…

Ow. Ow. That hurt. That really, really hurt. Sweet Celestia, that hurt.

Twilight was still babbling. “…And I promise that as soon as I figure out what in the name of the void I did to you, I will do everything I can to…”

I felt under my balls again, much more gently, this time. There was nothing there but the tightest ass in Equestria. Apparently I was a male, now. A colt. A stallion. A red-blooded, card-carrying, low-hanging, peeing-standing-up Equestrian male.

Speaking of peeing, I didn’t have to any more. That was weird.

“…and if there’s anything I can do to make you more comfortable, I…”

“Twilight.”

“…promise that I will do everything in my power to help you…”

“Twilight.”

“…but you have to understand that I can’t just reverse the spell. Magic doesn’t work that way, and…”

“Twilight!” I barked. I could be really loud, now, apparently. It felt good.

Twilight sparkle stared up at me, a look of abject horror on her face.

“Twilight, it’s okay.”

“You’re not mad at me?” Twilight squeaked.

I ran a hoof through my mane. “I’m not mad, Twilight.”

“But I turned you into a colt.”

“Yeah, but you got rid of my infection, too. So, mission accomplished, right?”

Twilight chuckled. “Heh. Yeah. I guess.”

I noticed Twi’s eyes dart up and down my body. I tried not to think anything of it. Even though her eyes were spending more time down than up. I was probably really scientifically interesting, now, right? “Hey, and it if it was going to happen to one of us, at least it was me, right? I mean, can you imagine if this had happened to Rarity? Or Fluttershy?”

Twilight twisted a thick strand of her mane around her hoof. “At least we know Fluttershy’d have a nice voice.”

I chuckled. “Well, yeah.” My nostrils flared as a faint but appealing scent drifted into my nostrils — the smell of a mare who wasn’t in season, but was down to party anyway. I felt the familiar feeling of lust in my groin, mixed with a strange, swollen, stiffening feeling. I felt something down there brush my belly fur. A quick glance confirmed that I was, in fact, getting my very first hard-on. And hey, I had an awesome dick — long and slim, with a cobalt blue shaft, mottled robin’s egg blue on the end.

Twilight had definitely noticed. She smiled up at me coyly, and said, “You have a really nice voice, too. It sounds a little like… like someone else I know.”

“Hey, thanks.” I found myself scooting slowly towards Twilight, a predatory grin growing on my face. I stared down at Twilight’s soft, pudgy belly, her plump thighs, her cute little teats that always looked like she’d just started nursing. I wanted it. I wanted it bad.

Twilight was trembling a little. “Rainbow?”

“Yeah?”

“I need you inside of me.”

So I pushed her roughly onto her back, and shoved my muzzle in between her legs. I inhaled deeply, her sweet, pungent scent filling my nostrils and blowing away whatever shreds of reason I had left. I gave her a big, slobbery lick to make sure she was wet enough, bit one of her nipples way too hard, and scrambled up on top of her, belly to belly. I cocked my hips, and started hammering away with my brand new dick, only to realize that I had no idea how to use the damn thing. The flat, uselessly blunt head went everywhere: Twilight’s navel, the inside of her thighs, everywhere but where I wanted it. I finally lodged up between her fat ass cheeks against her plothole. Desperate with lust, I had settled on trying for a dry anal fuck when Twilight’s horn glowed, her magic grabbing me painfully by the cock and yanking it upwards.

“Oh no!” squealed Twilight. “You are not going in there.” Her magic clenched around me and guided me up her cheeks to her moist, delicate flower. “Try that. Much more fun for everypony.”

I gasped as my cock slid past Twilight’s slick lips and into her body. The sensation was… well, new was the only way I could describe it. It felt a little like having my clit sucked on, but on a vastly larger scale. She was a good fit, deep and snug, but not too tight, so that I could get in all the way without too much trouble, and get right to humping.

“Holy Celestia,” I said, grinning down at my friend, “Twilight, your pussy feels amazing!”

Twi smirked, braced herself against the floor with her elbows, and hiked her rump off the cold stone. “You’re not bad yourself, stranger,” she huffed, wrapping her hind legs around my back and pulling herself onto me, hard. “Bonus points if you call me ‘Twilie’.”

“Isn’t… isn’t that… what your brother calls you?” I ground against Twilight’s groin, in balls deep, feeling her silky tunnel clenching and moving all around me. The filly was bucking her hips against me, our bodies slapping together roughly in midair.

“Don’t think about, it, baby,” she purred, eyes sparkling. “Just do what feels good. Even if you know it isn’t right.”

These Canterlot fillies were crazy in bed — sometimes they even weirded me out. “T-Twilie,” I moaned, experimentally.

“Oh, Shining!” gasped Twilight, her pussy clenching around my dick.

“Twilie, your pussy feels so good,” I groaned, grinning like a maniac. This was weird, but it sure got my blood flowing. I glanced left and right at Twi’s magnificent wings, spread across the floor. A princess. My first time out as a stallion, and I was fucking a princess. I mean, it was really just nerdy old Twi, so not, like, a real princess. But still, how awesome was I?

Pretty damn awesome.

“Oh, Shining, I love you.” She reached up to stroke my mane.

“And I love fucking you, Twilie,” I purred. Gotta keep the wording diplomatic, or it gets weird.

“Oh, Shining, Shining, Shining!” Her Highness was definitely starting to lose it. She tugged at my mane, and bit at my neck. Once, twice, the third time hard enough it felt like it broke the skin. I felt a flood of white hot pleasure rising up from my loins. No! It was too soon, and… what was that feeling? Something was coming out of my dick! Was it bleeding? I jerked roughly out of my friend’s pussy, spraying ropes of hot white jism across Twilight’s upthrust belly.

Oh. Right. The cum thing.

Twi’s overfed plot, deprived the support of my hips, slapped down on the cold floor. With a frustrated whimper, she pushed one hoof between her legs, working it frantically until she started shaking. She forced her other hoof into her mouth, biting back a scream, and her back arched as she came. Then she lay still, all four legs spread out across the floor, barrel heaving with gasps as my cum dried slowly on her belly and tail.

My heart sank. I’d come way too soon. She’d had to finish herself. I’d been a lousy lay. “I-I’m sorry, Twilight. This doesn’t usually happen. I…”

Twilight pushed herself up on her elbows. She was blushing and smiling. “You were wonderful. We should probably have a little talk about what just happened, though.”

“No.” I was not in the mood for a friendship talk. I launched myself into the air in a panic, only to be stopped cold when my head rammed into the arched, root-vaulted ceiling. “Ouch!”

“Rainbow! You need to listen to me!” Twilight sat up on her haunches. Normally, a good, or even mediocre fuck would leave me dying for more. But as a stallion, orgasm brought clarity, instead. All the lust was gone from my mind, replaced by fear. Fear of Twilight, with her dangerous magical experiments and creepily specific incest fantasies. Fear of this new body. And my old pal, fear of commitment. Where was the door?

“Rainbow, come back down here!”

The door was bolted several times. Trivial for a unicorn to unlock, but a pain in the ass for me to pull open with my teeth. So I just kicked it. This new body was even stronger than my old one, and the wood began to splinter satisfyingly with just one kick.

“Rainbow! Your body is flooded with unfamiliar hormones right now! You aren’t fit to be out in public!”

CRASH!

Twilight was shouting. “Specifically, the hormone testosterone. Which influences…”

CRASH!

“…sex drive…”

CRASH!

“…risk-taking…”

CRASH!

“…and aggression! None of which you need any more of!”

SLAM! The door came down, and I was through it. My wings were a blur as I zipped down the corridor and over the stairs up to the throne room, desperate to get out before Twilight remembered she could restrain me with her magic.

Twilight’s voice echoed down the corridor after me. “Rainbow Dash, you owe me a new door!”

Author's Notes:

My characters are really inconsistent about safe sex. You guys be more careful than they are, okay?