The Possibilities of Potions

Rainbow Dash touched down lightly on the grass. Ahead of her, the branches of the giant tree swayed gently in the summer breeze. Twilight Sparkle’s home, formerly a symbol of boredom and eggheadedness, had become a welcome sight since Rainbow had discovered the adventures of Daring Do three weeks ago. Still, as fun as reading her adventure stories could be, Rainbow had other things she wanted to be doing. Her wing was finally back in top shape, and she was dying to keep practicing her latest aerial maneuver, the Dashing Dazzler.

But a friend was a friend. Rainbow sighed, and held up the note again.

Dear Rainbow Dash,

I’m extremely sorry to bother you, and I know you must be busy, but I really need your help. If you have a few hours, could you meet me at the library around noon tomorrow?

Sincerely, Twilight Sparkle.

Rainbow sighed again. Knowing Twilight, she was shelving books or something, and needed an extra set of hooves. She’d help, but she didn’t think she’d enjoy it.

The door was shut tight when she arrived. Rainbow gave it a firm knock, waited for a moment, and then yelled, “Hey, Twilight! You in there?”

The top half of the door swung open. Twilight beamed at her through the opening. “You’re here! Excellent, we can get started right away.” She opened the bottom of the door and let Rainbow inside.

“So what did you need help with?” asked Rainbow, trying to hide her impatience.

“Sorry, Rainbow Dash.” Twilight looked sheepish. “Normally, I’d ask Spike or Pinkie to be my guinea pig, but Spike’s visiting Canterlot on business for the Princess, and Pinkie’s out of town—she mentioned something about a balloon tying competition.” Twilight shrugged. “Anyway, I need an assistant to help me catalog these items for study.”

Rainbow suppressed a groan. Cataloguing items? Great. This is going to be more boring than watching Tank try to play catch without his magicopter. She forced a smile. “What items?”

Twilight gestured behind her. The center of the library was occupied by a table covered with several boxes. Rainbow could see the tops of bottles poking out of them. She raised an eyebrow. “You’re not going to blow anything up this time, are you?”

“Hopefully not.” Twilight’s horn glowed, and one of the bottles rose from the box. It was filled with a clear, blue-tinted liquid. “These are potions that Zecora brewed for me. I asked her to give me a decent sampling of everything she knew how to make.”

“Er...” Rainbow leaned back. “You’re not sick or anything, are you?”

“No, no, they’re not all cures like her poison joke recipe.” Twilight set the potion down on the table, and scanned a sheet of paper lying beside the boxes. “Zebra magic is completely different from unicorn magic. We channel spells through our horns, but they use herbs and potions, among other things. What’s really interesting is that their alchemy can produce unique reactions and effects unseen in-”

Rainbow held up a hoof. “Whoa, Twilight, you’re losing me.”

Twilight rolled her eyes. “Zebras can do things unicorns can’t. I want to figure out how.”

“And you’re going to do that by cataloguing all these potions?”

“That’s just the first step. The second—and more important—step is where I need your help.” Twilight smiled. “We’re going to test them out! And monitor the effects, of course.”

“Wait, you’re going to have me drink a bunch of random magic potions?”

“Not random!” Twilight pointed back at the boxes. “I’ve labeled each set. These are the health brews, those are stimulants—I’m certain they’re why Zecora’s coffee is so strong—and this box has the most interesting bottles of them all.” She lifted the box labeled Alteration Potions off of the table, and set it down on the floor.

“Alteration?” Rainbow swallowed. “What’s going to happen? Will they turn me into a giant bug or something?”

“Nothing that drastic.” Twilight held up another bottle and shook it, eyeing the mixture. “But zebras can do some incredible things. Like age magic. It takes an extremely powerful unicorn to perform an age spell, but I’ve read about zebra potions transforming ponies into fillies and grandparents in an instant. I’m determined to figure out just what it is about these mixtures that produces such powerful effects.”

“I don’t know about this...” Rainbow eyed the box warily. “Are you sure it’s safe?”

“I wouldn’t ask you if I wasn’t.” Twilight smiled reassuringly. “But we’ll only do this if you’re okay with it.”

Come on, Rainbow, she’s counting on you. With her jaw set, Rainbow nodded. “All right, Twilight.”

“Great! I’ve got everything ready, we just need to start going through the potions one by one and record the effects. I’ll scan you for any magical auras and then administer the reversal agent.” Twilight’s horn glowed again, and one of the bottles rose from the box to float over to hover in the air, level with Rainbow’s head.

She took a deep breath, and grabbed the bottle in her teeth. Tipping her head back, she drank. The liquid burned mildly in her mouth as it went down, and she grimaced. “Tastes like mouthwash.”

“Hmm... it doesn’t have any alcohol content. I wonder what’s causing that sensation...” Twilight scratched some notes on her paper with a quill.

Rainbow bounced nervously on her hooves. “Am I turning into a giant bug?”

Twilight’s eyes widened slightly. “See for yourself.”

Looking down at her hooves, Rainbow found to her surprise that they were rapidly turning gray. The color seemed to be leaking out of her skin and evaporating into thin air. “Is this... is this supposed to happen?”

“Well, number forty-seven was labeled ‘Desaturation Draught.’ Oh, my! Your mane’s going too!” Twilight blinked.

Rainbow felt a flash of panic. She pulled her mane over in front of her face and squeaked. All the colors in her vibrant hair had been washed out. She looked like somepony from a moving picture on the weather patrol’s ancient projector. “Fix it!”

“Just a moment,” said Twilight, closing her eyes. Her horn glowed, and Rainbow felt a tingle as Twilight examined the pegasus for magical effects. “How interesting,” she murmured.

“Great, great, interesting, can we please get my color back?”

Twilight’s eyes snapped open. “Sorry, sorry! Let me get the antagonist.” She dug into the box, rifling through several bottles before pulling out a red one. “Here we go, ‘Creme de Color.’ Just a mouthful, you don’t want to be walking around in neon.” Twilight handed her the potion, and she poured it down her throat.

Slowly, Rainbow felt a warm, pleasant sensation bubbling up through her. She watched her mane intently, and was relieved to see it blossom into color like a blooming flower. “None of these are going to be permanent, are they?”

“They shouldn’t be.” Twilight sorted through the box, looking for the next bottle to try out. “Zecora told me she’d intentionally made light doses. They should wear off in a few hours if we don’t reverse them earlier than that.”

The next potion tasted sweet, like honey. Rainbow licked her lips. “I like this one.”

Twilight waited for a few moments, and then frowned. “It doesn’t look like anything’s happening.”

“I don’t feel any different.” Rainbow blinked. “Hang on, I’m seeing—you look weird.”

“Huh?”

“It’s like you’re glowing, or something, and the candles are, too.” Rainbow made a little ooh sound.

“Really! It sounds like you’re seeing in the infrared spectrum, Rainbow Dash.” Twilight’s quill scratched furiously. “I’m saving that one to use with my telescope.” She set the bottle aside.

They continued testing potions. Rainbow found herself beginning to enjoy the experiments. Some of the potions did strange things to her, like the one that made her tail and mane start growing uncontrollably, but others were undeniably cool, like the one that turned her waterproof. They tested that one out by dumping a bucket of water over her. All the water just splashed to the floor, leaving Rainbow totally dry. Twilight got rid of the mess with a handy liquid-removing spell she’d learned a few months ago.

“Let’s do this one next,” said Twilight, holding up a bottle of black liquid.

Rainbow chugged the bottle, setting it down and wiping her lips. “Well?”

Twilight’s eyebrows shot up. “Rainbow!”

“Hmm?” Rainbow looked over her back to see if she’d turned purple again, and froze in shock. Her feathers were falling out.

“Ahhh!” she yelled, flapping her wings frantically. More feathers drifted slowly to the ground. “Fixitfixitfixit!”

Twilight rummaged through the box. “Hang on, hang on... no, no, not that one, no, no, no... Where’d number sixty-two go?”

Rainbow shoved her aside and scanned the bottles with the sharpest eyes in Ponyville. She spotted sixty-two, and reached down to snag it. Quickly pulling out the stopper, she drank the potion in a swift gulp.

The seconds passed, but her wings continued to molt. She blinked at Twilight. “You said sixty-two, right?”

“Yes! ‘Feather Fizz’ should’ve fixed this, I don’t—” Twilight paused.

“What?” Rainbow tilted her head.

“I don’t think you drank the right potion...”

Suddenly, Rainbow felt a bizarre stretching sensation. Her muzzle felt like it was expanding, jutting out and becoming blockier. Her legs bent suddenly as they, too, began stretching. They thickened, the curves of her legs straightening.

Her face contorted with discomfort, and she groaned, “Quick, give me the right one!” Twilight pulled up a bottle, checked the number, nodded to herself, and then stuck it in Rainbow’s mouth. She chugged it, and suddenly her wings felt like pincushions. A thousand tiny needles poked her wings, as new feathers burst forth to replace the ones now lying on the ground.

“Thank Celestia.” Rainbow’s voice sounded strange to her ears, slightly deeper than normal. Another bout of stretching pain came over her, and she twisted. “Ow! What—what did I drink?”

The next change made it suddenly clear. Rainbow felt a new, unfamiliar something brush against her stomach. Even more strange, the brushing sensation wasn’t coming from her belly itself. The obvious answer was too ludicrous for her to consider right away.

“Well,” said Twilight, her voice slightly higher-pitched than usual, “I think we found the stallion transformation potion.”

“St-stallion transformation?” Rainbow’s voice was definitely lower than normal. She blinked, staring down at her too-large hooves. “I didn’t think you could—”

“Unicorns can’t,” said Twilight, still looking a little alarmed. “Like I said, zebra magic can do some weird things.”

“Uh.” Rainbow blinked. She—he?—no, Rainbow decided, still she; whatever her physical body, inside she was still the same old Rainbow Dash.

But what the hay was going on with her body?

“Fascinating,” said Twilight, walking around her with her notebook. “The transformation seems pretty thorough. Your anatomy is totally different.”

Anatomy? Rainbow swallowed. “Er...”

“Your bones are much blockier, and your legs are thicker. Hmm...” Twilight jotted down more notes. “I wonder how deep the transformation goes. You think your chromosomes have changed?”

“My kroma-whats?” Rainbow felt a drop of sweat drip down her forehead. “Er, do you think we could change me back now?” She felt very strange. Her body was too heavy, weighted down by all the extra bone and muscle mass.

“Wait a minute or two, I’d like to get some data on this. It’s one of the first uniquely zebra magical effects we’ve come across today.” Twilight poked Rainbow’s flank, making her jump.

“Hey!”

“Sorry. Subject reacts to stimuli... nerves appear fully functional.” Twilight paused as her quill ran dry, and moved back to re-ink it.

Rainbow took the opportunity to examine her new—and, she trusted, temporary—body. Her mane felt coarser, and her mouth was bigger. She felt taller, too. Though she was definitely not built as big as, say, Applejack’s brother, she could look over Twilight’s head without stretching her neck, now.

And then there was the other thing. The thing that had appeared between her legs, in the most unexpected attack of stretching. She looked up at Twilight. Seeing the unicorn still absorbed in her notes, Rainbow turned her back, and sat down to examine her new body part.

It was half-extended from its sheath, a marbled blue-and-black shaft with a flattened head. Rainbow blinked, still not quite believing it. A dick. I have a dick.

A tiny voice in her head piped up, I wonder how it feels?

She quashed it instantly, blushing. Hopefully, Twilight would finish her notes and give Rainbow the antidote soon. Then she’d be back in her old body, and wouldn’t have to deal with all these new sensations.

Seems like a shame to lose it without even trying it out, though.

Did stallions always think like this? Granted, Rainbow had met a few with one-track minds, but she had hoped it wasn’t universal. Despite her efforts to turn her mind to other things, she couldn’t help but stare at her slowly hardening member.

“All right, Rainbow Dash, I’d like to get a sample of your tissue.”

Rainbow heard Twilight’s hooves thud on the floor and jerked upright. “Wait, what?” She twisted her head to see Twilight approaching with a syringe held by her magic. “Whoa, you’re not planning to stab me with that, are you?”

Twilight held up a calming hoof. “Relax, Rainbow, it won’t hurt very much. I just need a blood sam—sample, to—uh...” Her eyes widened.

Rainbow realized that when she’d turned, she’d revealed her half-stiff cock to her friend. Her face went beet-red. “Um.”

“A... very thorough transformation.” She bit her lip, and whispered under her breath, “I wonder if that’s why they made the recipe...”

Rainbow pretended not to hear. “Look, can I please take the anti-whatever now?”

“I still need a tissue sample.” Twilight half-opened her mouth, then bit her lip. “If you don’t want to use the needle, there’s another way.”

“Okay, fine, whatever gets me back to being me.” Rainbow wiped her forehead.

“It might be for the best, anyway. I’m curious if... well, if that is functional.”

Rainbow gave her a scandalized look. “You want me to pee?”

“Well, no.” Twilight looked sheepish. Her cheeks tinged pink. “There’s no DNA in urine.”

“You mean—” Rainbow choked. “Uh, Twilight, you’re saying you want me to, like... get off?”

“For posterity,” said Twilight, a little too quickly. “Besides, aren’t you curious?”

Extremely. “Not really...” Rainbow sat back on her haunches, staring down at the lengthening shaft of her stallionhood. “But I guess... I mean, if it’s this or getting stabbed, I guess I’ll take this.” She swallowed. “So. Uh.”

Twilight was looking quite flustered by now. “I suppose you ought to, um, stimulate yourself.”

Rainbow lifted a hoof and looked at it uncertainly. She slowly brought it down to rest on her hardening dick. It felt hard and soft at the same time, like velvet over iron. Slowly, she ran her hoof down the length of her shaft, inhaling at the touch.

She moved her hoof back up to the top and rested it there, watching as a tiny white bead emerged from the tip. Well, there’s Twilight’s sample, she thought dryly, but she continued moving her hoof across her head. It smeared the tiny drop of liquid across the flared tip of her cock, and she felt it twitch. She spared a glance up at Twilight, who was watching intently.

Rainbow began moving her hoof up and down, feeling it slide along her sensitive skin. She breathed deeply, matching her slow strokes. Her cock was beginning to ache with need. She gritted her teeth and continued to rub it softly.

Motion drew her attention. Twilight looked extremely uncomfortable, standing stiffly with her lips pressed together. Why is she looking nervous? I’m the one playing with myself in front of her. Rainbow closed her eyes and breathed out. She had to admit, this felt good.

She brought her other foreleg over and began rubbing both of her hooves along the sides of her stallionhood. Every time they passed over the little ring in the middle of her length, she felt a tiny tingle of pleasure.

Twilight cleared her throat. “So, Rainbow, ah... how’s it feel?”

“Really... mmm, really good.” Rainbow began stroking faster, tugging on herself with every upward stroke. She folded her right wing around her shoulder, and bit down on her tip feathers like she always did when she played with herself. Granted, usually she didn’t need both hooves...

Her head was getting cloudy with heat and anticipation. Increasing the pace of her strokes, she gave another murmur of excitement. The throbbing feeling in her cock was only getting stronger, but it was a good kind of pain. She licked her lips.

Sparing another look up at Twilight, Rainbow found her friend staring wide-eyed and sweating. She grinned, as her inner performer took over. Whether it was aerial maneuvers of daring skill, or slippery, hot self-pleasure, Rainbow Dash was comfortable in front of crowds. She tilted her head back. “Enjoying the show?” she asked, joking.

To her surprise, Twilight blushed redder, and squeezed her back legs together. “Very... educational.”

Rainbow raised an eyebrow. “Educational, huh?” She took her hooves off of her dick and sat back. “Maybe we should stop for now. You’re looking a little flushed.”

“I’m fine,” said Twilight, blushing more. “Just a little hot. All the library windows are closed.”

You weren’t sweating during the last two hours we spent in here. Rainbow grinned again. “Want me to keep going?”

“Please,” Twilight said, before slapping a hoof to her mouth.

“All right, then.” Rainbow lay down on her back and let her rock-hard erection stand free. It wobbled a bit, and she felt some satisfaction as Twilight squeezed her legs together again. Rainbow reached her hooves up to her mouth, and one by one, spat on them. Then she took her hooves and put them back on her shaft, and began pumping them up and down.

Her pace was much faster, now. She began to breath heavily, stroking up and down and up and down. They glided over her saliva-dampened cock, going schlick schlick schlick. She felt a moan escape her, as her stallionhood twitched again.

It wouldn’t be long, now. Rainbow was panting, furiously rubbing herself as she neared the finish line. She looked at Twilight, and found herself imagining her friend lying down with her legs spread out, pussy gaping wide to take Rainbow inside her. The unexpected image made her gasp in shock, and she felt an approaching wave of tension in her pelvis.

The wave crashed forward, and Rainbow felt herself pass the point of no return. “Twilight—I’m—oh!”
A fountain of white burst from the tip of her cock, arcing through the air. Rainbow shook as the tremors rocked her, sending shot after shot of hot, sticky cum flying. Her hooves kept pumping, and she rode her climax to the end, her chest heaving.

At last, the aftershocks began to fade. She opened her eyes and saw the trail of white across the floor, leading back to her dribbling cock. Rainbow panted, raising her head to see what Twilight was doing.

The unicorn was still staring at the stream of cum that Rainbow had shot across the wood. Her lips parted, and she said, “W-well, that should do nicely for the tissue sample. I’ll just collect it...”

Her horn glowed, and an empty bottle rose in the air. The sticky liquid glowed purple, and it lifted off of the wood to pour into the bottle. Rainbow grinned. “Maybe I should keep you around for cleanup, Twi.”

Twilight gave a shaky laugh. “I, uh, guess we should move on to the next one.”

Rainbow watched as she started sorting through the bottles in the box. Twilight’s tail was swishing back and forth in a nervous rhythm. Rainbow caught glimpses of something glistening beneath it. “Twi, you feeling okay?”

“J-just great!” Twilight smiled at her. “It’s just a little strange seeing you with...”

“With a cock?” finished Rainbow.

Twilight blushed. “Yes.”

Rainbow grinned. “Look, if you need a few minutes alone...”

“Rainbow!” Twilight’s cheeks threatened to catch fire.

“What? I can’t believe you’re being modest after that. I just came all over your floor. If you’re feeling a little... tense, just say so.”

Twilight swallowed. “Okay, I admit it. That was really hot. I’m feeling very...”

“Horny?” Rainbow smirked.

“Yes,” said Twilight, through clenched teeth. “Yes, I’m feeling ridiculously horny.”

“Well, if you want, and you ask nicely, I can help you with that.” Rainbow stood, and brushed past Twilight, flicking her with her tail.

Twilight looked shocked, but her protests seemed to get lost somewhere between her throat and her mouth. Her dry, thirsty-looking mouth. Rainbow rubbed past her side, raising her tail. “Tongue-tied, Twi?”

“You’d—you’d do that?” Twilight sounded half-excited, half-mortified.

“Sure! What are friends for? Besides,” said Rainbow, rubbing her nose against Twilight’s cutie mark and drawing a slight gasp of air, “I’m equipped for it.”