Fluttershy had been sitting outside in the winter chill for the last few minutes trying to figure out what to do. She was right in front of Twilight's castle and working through exactly what she would say to the alicorn. Not like she was doing something outright illicit or illegal, far from it, it was just that Flutttershy's request was a bit out of character for the mare- at least publicly, she had a near spotless reputation for being rather demure and quiet when the topics of sex and other adult things came up.

In private though, it was a different matter.

Fluttershy sighed and pushed open the doors, her mind fully made up on asking Twilight about her idea for Dash's Hearthswarming present- and thanks to Dash's brazen moods and penchant for stealing each and every potion or tincture Twilight had ever made for "pony testing", Fluttershy could just say that it was something Dash had mentioned wanting to try out. It wasn't like it was an outright lie- Dash loved the way certain potions messed with her anatomy and gave the pair of pegasi new ways to screw like rabbits. It was just that, for once, Fluttershy wanted a potion that both would love.

Twilight walked into the large entrance and smiled as she noticed who had walked in. "Hey, Fluttershy what's up." The alicorn was used to solving problems for the entire surrounding area- as an alicorn it was sort of her job.

Fluttershy tapped her hooves together and tried to let the words come out naturally, but her nerves made her stumble over them. "I, uh. . .this might sound really odd coming from me, but with Hearthswarming here. . .I mean I was trying to come up with a present for her and I just really had one idea. I mean I had others but since she's already a Wonderbolt, its no like getting Wonderbolt branded presents would be that interesting. But then I thought Dash would really like something to spice up our relationship. Not like we have problems there but. . ."

Twilight nodded, vaguely understanding what Fluttershy was getting to. She knew the pair of pegasi were at least a couple, though she sometimes wondered what Fluttershy saw in Dash- their personalities were just so different, not to mention that Dash was what Applejack termed, "a functioning alcoholic" during cider season. Compared to the pony standing in front of her that could barely string a sentence together without being worried. . .yeah she couldn't understand how the pair worked. "Okay so you want something to excite your time in the bedroom?" Twilight sighed. She had become numb to the fact that most of her friends' friendship problems now were entirely sexual in nature. She wondered if Cadance had a similar issue as the Alicorn of Love. "What were you thinking about doing?"

Fluttershy eeped and hid behind her mane for a second as she prepared for the worst. "It's Dash's idea. She mentioned it once or twice and well, I wrote it down just so you wouldn't incorrectly make it. Not like that would happen." She opened up her winter coat's pocket with a hoof and passed the note to Twilight.

Twilight carefully read the note and sighed. "Fuck, I should have predicted this." Twilight rolled her eyes and cursed that her ascension to alicornhood had made her extremely horny and sex obsessed for a good few years. That had warped each of her experiments for a while into dissertations on the joys of sex and how to increase certain attributes, or even to change genders on the fly. For science and pleasure of course. She had a good run of dissertations that certain unicorn scholars used for the basis of sex magic. It just felt awkward because she had expected to help magic studies overall with her research- at least how friendship nestled into magic- but no, its niche sex magic that made her semi famous now."Let's see, one potion to give Dash a cock. . ." Twilight raised an eyebrow at that.

Fluttershy flushed crimson. "Her words." They weren't, she had just been in the mood when thinking this note up. She had spent a good ten minutes imagining Dash with a cock big enough the much larger pegasus could feel explicitly when they had sex.

"-and balls. Make it really potent cause Dash has some potion immunity due to all the. . .damn it I should have known she was the one stealing each and every one of my experiments." Twilight grumbled. "I don't think potion immunity is a thing, but sure, whatever floats Dash's boat. One extremely potent dick potion coming up. Like this isn't going to bite me in the ass somehow sooner or later." Twilight sighed. At least it wasn't as weird as some of Pinkie's potions she begged the alicorn for- turning the pink mare into living gingerbread so Pinkie could fill herself with cream filling was a new one. This was rather banal compared to that.

Fluttershy followed Twilight into the alicorn's lab and quietly marveled at all the collected brews and potions that lined the walls, crystal carafes and small beakers full of ingredients that the pegasi was unfamiliar with- her own expertise more in the animal realm and less on the wild world of plants. Sure Fluttershy knew enough home remedies to patch up most scrapes and falls which was super useful since her marefriend was prone to flying face first into trees or the sides of mountains when she was distracted, but Twilight's stash of dried plants looked to cover the rarest and oddest specimens from around the world.

Twilight flitted through the botany collection and talked to herself as she gathered the items necessary for Fluttershy's flight of fancy. "Let's see, this gift idea for Dash would have been so much easier if one of you was a unicorn, no offense, but replicating the spell matrices for a penis poof spell- no that isn't the technical term, just Rarity's cute joke name for it- would just involve me giving you the instructions and letting you two go to town. Without that I have to pull ideas from a lot of places- a general idea of Zebrican aphrodisiacs and potion crafting I learned from Zecora, the botany theories from the Botanical University of Dusky Shades, some Crystal Pony magic theory. Hell, I'll throw in some zingers from Changeling emotional spells and replicate them by adding a few hints of lavender and chili peppers to balance out the sweetness of this brew."

Fluttershy nodded. She vaguely understood what Twilight was talking about, even if she could only get every second or third word cause the mare was speaking in a speed and cadence that definitely hinted that the alicorn was in her element. The others had become used to Twilight's moods and usually when the alicorn got like this, everypony just went with it since Spike was one of the only creatures that could follow the tangents and turns of phrase that Twilight used.

Twilight plopped a massive hooffull of herbs, flowers, and spices into a nearby mortar and smashed them all together with a pestle and hummed to herself as she quickly made the myriad plants into a paste. "Okay, now I just have to strain this to get out the seeds and put it in a suspension of distilled water and say a quick few spells to bind everything together. Generally simple process- you should have seen the nightmare when I was starting out doing syncretic magical spells and potions, this place was more often on fire or worse- pony testing had some unfortunate results. Nice ones for the process, but turning into a one foot tall pony when I had attempted to increase certain attributes was not what I wanted."

Fluttershy raised an eyebrow. "Sounds. . .fun?"

Twilight sighed. "It was and I got creative with it, but I am glad that wore off." Twilight mumbled a few magical tinged words over the mixture and the potion turned into a deep dark golden color. Fluttershy smiled as it almost looked like one of Dash's mugs of cider and the pegasi had an uncharacteristically devious idea as the brew was passed to her.

"Now with this being way, way more potent than most potions I give out, I have to go over a few safety precautions. Not that I expect Dash to follow any of them since you and I know her and my warnings go in one ear and out the other-" Twilight sighed. "Use only a teaspoonful of this stuff." She shook the small bottle. "I'd say you have. . .fifteen? Twenty doses? Enough for a month of random fun. I'm just saying this cause most potions work on a dosage requirement and overdosing on this can have cumulative effects."

Fluttershy nodded, her mind filling in what 'cumulative' meant and she liked the results her imagination gave out. She reflexively rubbed her nethers together and listened intently.

"And if that happens, well, the potion effects may be somewhat permanent. Like it will go down to a general baseline sense of normalcy but an overdose of substantial amounts would be rather life altering." Twilight punctuated that with a tap of her hoof on the small vial. "and tell Dash to limit her alcohol intake. I don't know exactly how this potion works when inebriated. So have her drink as little as possible."

Fluttershy nodded and smiled as she put Dash's present that neither would forget into her satchel and dashed out relatively quickly for the mare.

Twilight blinked and sighed. "Okay, well I didn't get to tertiary warnings since this stuff isn't written down. Eh, they'll work it out." The alicorn rolled her eyes. "-still I didn't even get to the hypothetical transitive nature of potions and sharing bodily fluids or if this is slightly addictive or not." Twilight shrugged. "I probably have an eighty percent chance this blows up in my face somehow, but maybe Celestia might enjoy a lighter holiday letter this year with just a. . .what was the word Spike used? Wacky? A wacky friendship problem. At least this shouldn't be as bad as the Smarty Pants situation. Any more prodding and that could have turned into an orgy.

***

Dash carefully flew through Ponyville, her Wonderbolt uniform giving her some protection from the cold as she banked into the final turn to Fluttershy's cottage. She had gotten time off due to the holidays and unless Fleetfoot caused an international incident or something, Dash could plan for a few days off from training. Not that she minded training with the Wonderbolts, it was all her hopes and dreams- just the uniforms left little to the imagination. She grinned as she remembered Shy's first time seeing Dash in uniform, the normally demure mare had become her loudest fan as Dash gave the butter yellow pegasus a bit of a show.

Not like the other Wonderbolts didn't notice. After her first performance they had to pull her aside and mention that 'while they understood celebrating, the fact of sexually flaunting your goods so openly in a generally family friendly environment was grounds for some form of reprisal'. Dash had to get that simplified and while she understood it, its not like the brash pegasus didn't notice a few teammates getting frisky before shows.

She guessed it was just the time and place.

Dash smiled at that thought. If she couldn't do things so publicly, then her costume had become a wonderful way to spice up the pair's sex life. The form fitting latex and lycra stretched over her meager curves and athletic body leaving little to the imagination and she had pulled her uniform out of her locker for that reason.

She rubbed her legs together as she imagined Fluttershy nuzzling her and rubbing against her in all the right ways. Shaking her head, she strode into Fluttershy's cottage- since the two mares were so used to each other's company it wasn't too weird for Dash to barge in nearly unannounced. And if Shy was in the mood, that usually meant it was sex time and Dash loved sex time. "Hey, I'm back. You know from Canterlot and I definitely need to be armed up cause its really coming down out there."

A clattering of hooves came from the kitchen and a slight yelp and light sanitized swearing could be heard. Huh, must have surprised Shy or something. Dash hummed to herself, thinking how fun it was that Fluttershy was one of the hottest- and sex crazed mares- Dash knew. She laughed at that thought since it rarely came up in public situations. Not like Shy wouldn't pull out the sex toys in public fun, just Dash was usually the one who got stuck with pulling off all the public exhibitions since Fluttershy was a kink laden mare but her natural proclivities made her nervous and afraid.

Unfortunately that kind of made Dash look like the horniest mare in her six friends and she often got some mention of her horndog nature by Rarity or Applejack. And sure, Dash loved putting random magical liquids in her mouth to see what dumb fun effects would result, but that was just her natural curiosity. "You okay in there, Shy? Need any help?"

Fluttershy's weak and nervous voice came through the doorway. "N-no, I'm fine. You just surprised me is all."

***

Fluttershy was not okay. She had expected Rainbow to be back from Canterlot a lot later. The yellow pegasus had wanted to dose some hot cocoa with Twilight's little potion and had grabbed her measuring teaspoons to dose the chocolate brew with a safe amount of the potion. She was a horny mare, but she didn't want to go to Twilight with a "oh no, now Dash is half cock by weight" problem or something equally ridiculous. She could imagine the alicorn's stern look of disappointment if that happened.

So she had been carefully dosing the correct amount of the potion when Dash had come in and accidentally surprised her. Not usually a problem, not in the slightest, but this time the grip her wings had on the bottle slipped due to her involuntary surprise and the open potion fell with a dull splash into the wonderful hot chocolate.

Fluttershy's eyes sank as the bottle bobbed in the liquid and she was just so peeved off about it she could almost, but not quite, yell. She tried to fish out the small glass bottle with a ladle and was able to get it out with some fair wrangling and careful moves since she would rather not scald her wings or skin with hot liquid.

"Come on, come on, come on. Almost there." Fluttershy felt a tinge of relief as the bottle was lifted from the pot. That did not last long as she noticed that while the flask was out of the liquid, the bottle was empty barring a slight bit of murky brown hot cocoa in the bottom.

The potion was sitting right there on the stove mixing with the hot chocolate and only Fluttershy knew the truth.

"Oh sweet, hot chocolate. You shouldn't have Shy." Dash came up and hugged her, the small mare only coming up to her shoulder as she leaned into the hug. Fluttershy grimaced as Dash flitted around the kitchen looking for cups. "Hey so you want a cup or not?"

Fluttershy shook her head weakly. "No, I'm good. I, uh, made this for you."

Dash hoofpumped the air. "Rad." The blue pegasus blew a teasing kiss to her mare and grabbed a large glass. "Hey, where's the vodka? I want to see what that mix tastes like since the other Bolts were talking about how nice alcohol was in holiday stuff. And like doesn't it warm you up after you get cold? I thought I heard that."

Fluttershy's face whitened as Twilight's rules for this special potion echoed through her head, her natural proclivity for telling the truth was being tested- she both wanted to follow Twilight's rule of "no alcohol" and also warn Dash that drinking the cocoa was probably the worst idea ever. She thought of ways to distract the small mare- going out in the snow and having sex in a snowbank, flying off and enjoying the scenery on a cloud and possibly having sex- she grimaced as she realized that most of the successful distractions with Dash involved sex. Breathing out, she weighed her options. On one hoof, staying silent would ruin the Heartswarming surprise and that was just no good. On the other, if she spoiled the surprise Dash might just say fuck it and drink the whole thing just to see what happened.

It was Rainbow. She lived off bravado, competition, and a 'you can't tell me what to do' attitude.

Fluttershy sighed and pointed to the cabinet and watched Dash grab a small bit of vodka and splash it into the small pot and quickly ladle out a large serving of hot cocoa. If the quiet pegasus didn't know how bad an idea drinking it was she might have taken a sip or two.

Dash cheered her much taller mate and took a large gulp of the still hot cocoa. Dash liked to live dangerously and burning the roof of her mouth wasn't out of the question. "Nice."

Fluttershy closed her eyes as she waited for the potion to work.

***

Rainbow Dash stared at the Heartswarming decorations that littered Fluttershy's cottage, the twinliking lights and tree, the ornaments all hung up- all nice and good but Dash's favorite was the sprig of mistletoe that the blue pegasus always hid somewhere in the room so she could sneak up and casually plant a kiss on her mare's neck and slowly trace her way down towards Fluttershy's pleasure cave that Dash always liked spelunking in. She had read that word in a Daring Do book and after a long explanation on its meaning by Twilight, the word had slowly grown to be Rainbow's favorite. It was just so versatile and fun. And since Dash was the walking definition of a pride flag, she loved exploring Fluttershy's tight cave.

She blinked and looked down at her hooves and felt something off for a moment. Sure, she was getting all hot and bothered, she couldn't help it since Fluttershy was stacked like a brick shithouse with curves that went on for days but there was something else that felt off. And she had enough experience to guess what was wrong.

"Oh I see somepony gave me my present early didn't-" Dash didn't finish the sentence as the strongest orgasm she had in years hit her and turned her Wonderbolts uniform nearly see through as she sweated though her uniform up top and her love nectar flooded her bottom half and quickly soaked the blue lycra right through. She gripped the nearby table with a hoof and kicked her back hooves in response as she felt something thick push from inside her.

She whinnied as a dick pressed out from her inner sanctum and she took a few unsteady breaths as she looked down to see a rather respectable horsecock trapped in her skintight suit, the footlong bulge and its extra apple sized equipment looking obscene on Dash's half sized frame. "Holy fuck. This is. . ."

"Horrible? Terrible? The worst thing ever?" Fluttershy's worried voice unsteadily spoke as she tried to gather her thoughts. Having a front row seat to your marefriend growing a penis was probably the hottest thing the two pegasi had ever seen outside of spell pornos, but Dash's worried face as the potion took effect had crushed the yellow pegasus' confidence in her actions.

"No, I was going to say the best gift ever!" Dash stroked her new package and ran a hoof over her new balls, gently lifting them to test out the weight and giggling to herself as they smacked against her thigh. She lightly touched her dick and an electric shock of pleasure ran up her spine as she felt new pleasure receptors that didn't exist mere minutes ago start firing. "Oh Celestia, I can see why Thunderlane and Soarin' can't shut up about their dicks. I mean its still weird and Spitfire calls it 'workplace harassment' that would look bad on the team but now their comparing dick sizes makes sense. Cause I'd be competitive about my dick too." Dash smiled and glanced at her cup. "Or I would have been if a potion didn't give me a fun idea."

Fluttershy's eyes shrunk to pinpricks. "That would be a terrible idea. I mean if one drink could do this. . .Twilight warned me not to use too much. . .she had rules not to do something that reckless, I mean."

Dash rolled her eyes. If the blue pegasus followed every rule Twilight set. she'd become bored to death. The alicorn had unknowable spells and potions and nearly unlimited magic and the mare ruined the potential for fun with 'Dash, you shouldn't touch stuff cause you never listen to me. . .blah blah blah.' it was awful. It wasn’t her fault that Twilight’s warnings all sounded like a foghorn blaring in her head when the unicorn started on dangerous side effects- shit was boring. "Okay hit me with the rules and I'll see what I can do to loophole through them."

Fluttershy hid in her mane for a moment, tapping her hooves together furiously. "Don't mix with alcohol. . ."

"Which I did. And stop. Okay so Twilight made a potion that shouldn't be used with booze and gave it to you. That's almost like she asked for trouble I mean I'm like the. . .second best. . .alcoholic of our friends. And that's only cause Applejack beat me one time when I had already pregamed the drinking contest. I mean terrible idea in hindsight, but the cider just was too good. What I'm saying is there's like 90 percent of that pot left and Twilight works in mysterious ways. Like inverse psychotherapy. Or however she worded it."

Reverse psychology."

Dash rolled her eyes. "You know what I meant. But that."

Fluttershy stared at Dash with a worried look on her face. "I really don't think this is a good idea."

Dash crossed her hooves. "Fluttershy, I have three days off from the Wonderbolts, a new dick, and tasty hot chocolate that most likely will make my dick stupidly huge. It's a terrible idea but I'm going to bone the shit out of you with this-" Dash suggestively pointed at her rock hard erection. "and so help me I'm going to make this Hearthswarming memorable so help me Celestia."

"Twilight said it might be permanent. I mean an overdose of it at least." Fluttershy blurted out the fear that had been brewing in the back of her head since Dash had taken the first sip of tainted cocoa. "We should be careful."

Dash weighed the options and shrugged. "Eh, whatever Twilight will fix it anyway. Or if it gets unwieldy I can just ask Rarity to make enchanted underwear. Like unicorns probably have that shit cause you and I know puberty and magic has led to terrible ideas.

"W-well."

***

Dash stared at the cooled cocoa and grinned as she unzipped the secret zipper that her Wonderbolt uniform had in case of emergencies- sexual or otherwise- and snaked her respectable dick into the open air, the stiff rod at attention for what was coming next. She felt Fluttershy crawl under the table and nuzzle her cheek against it and stroke the newly gained orbs that were still trapped in the lycra unform with a gentle hoof. The to go zipper was not a perfect system- from how Soarin' complained about the ball room, it wasn't made to be fully comfortable. It was designed to be functional.

"Ready." Fluttershy's breathy voice came from under the table and Dash knew that tone of hers. Dash loved the slight switch in tone- most ponies wouldn't be able to tell that Fluttershy was in the mood, even if the yellow pegasus probably thought this was top five of Dash's worst ideas, the hitch in Shy's breath and nervous flutters of her hooves told her all she had to know. Well that and the faint hint of Shy's vanilla scent that told Dash that there was some liquid nectar flowing.

Or as Dash liked joking that Shy kept springing leaks and she needed a good quick plumber to fix it. Dash was the plumber. She was terrible at metaphors, but she got the job done.

Dash channeled her years of binge drinking for this moment and tipped back the pot, careful not to drink too fast as while she wanted the biggest dick she could get as fast as possible- she was Equestria's number one speedster for a reason- she didn't want to waste a single drop cause it was a mostly untested potion and she didn't want random woodland creatures to get to it. She already thought Angel was a dick, the rabbit didn't need help in that department.

She chugged the potion like there was no tomorrow and within what felt like a few minutes she stared at the bottom of the pot and sat there slightly tapping her front hooves on he kitchen table as she waited for the potion to work. Usually Twilight's homebrewed shit was way faster than this- the alicorn was focused on 'solving the most massive issues in the world and finding creative solutions.' She wasn't as focused on speed as the blue blur of a pegasus, but when she made stuff it worked relatively quick. . .

That thought hit Dash's brain like a ton of bricks as the potion worked overtime, spell matrices and forgotten knowledge mixed together with foreign spells took some time to work through the system and get things started.

What Dash didn't know was that her 'respectable dick' was from a small dose of the potion- and Potion Making 101 in Canterlot University usually started with the warning that overdosing on random potions, while fun, were often exponential and in most cases led to some odd effects.

Or as Dash would put it ever so bluntly: "weird shit".

What she didn't know was that her dick wasn't done growing- far from it.

***

Fluttershy was conflicted, sure, but as she ran a hoof over her nethers and touched herself to the brink of climax at the thought of what was to come, her worried slipped from her mind. She kept an eye on the prize and ran a hoof around Dash's new dick and smiled as she ran through the rainbow bush of her best friend. She had a silly thought that the cock and its dark blue color reminded her of a popsicle and if she deepthroated the flared tip it might spew out blue raspberry cum. She filed away that thought, giggling at the ludicrous thought- it could be an interesting idea for Twilight though. She would have to tell Twilight that Dash had that idea since Twilight expected that kind of lewd idea from the small mare, not her.

She broke out of her kinky reverie as Dash's balls audibly gurgled with seed and the Wonderbolts uniform lightly creaked as the skin tight outfit started to slightly inch outwards around the slowly growing bulge. Shy scooted back in preparation for what was to come. She wasn't dumb and while she wanted to worship that pillar of meat like a faithful devotee, she didn't want to walk up to her weekly spa day with Rarity with an accidental black eye because she sat too close and the growing dong knocked her flat on her back. That would be an interesting conversation that the yellow pegasus wanted to avoid at all costs.

She visibly watched Dash's new equipment bloat and lengthen. She quickened her pace of her masturbation session and edged herself into an orgasm and cried out in blissful abandon over the potion's work.

***

Dash sighed and looked down at her new equipment. "You know I thought this would be bigger. Like its big and all but its a Twilight potion, so I expected it to get like way stupider." Dash flopped her dick around to make her point, the virile stallionhood weighing heavy on her now widened stance. "I mean its big but I'm like half as tall as you are, Shy, this'd probably look normal on you." Dash crossed her hooves and leaned back on a chair in thought. "Like I'm not disappointed at all, but doubling in size after all that? Slightly disappointing."

Fluttershy stared at the dick and blushed. "I mean maybe, but it's still perfectly big enough and maybe you'd feel better if you actually got to test it out." The yellow pegasus looked away as she imagined her own waves of pleasure that would result in having Dash's new dick probe her inner depths.

Dash nodded and leaned back in the chair, ready for whatever fun her plush mountain of a marefriend would do.

Fluttershy slid up to Dash and straddled her, carefully aiming the blue pole towards her and inching her way down. She breathed out as she felt it stretch her. She cooed as she leaned into Dash, the chair creaking slightly under both of their weights. "Come on Dash, go fast."

Dash grinned and pushed upwards as fast as she could, the added weights of her lower half slowing her down at first as she figured out how to balance her weight. She thrusted up as hard as she could. She grunted as she felt Fluttershy's entire weight lift up for a second or two at the top of the thrust and settle back down- liftoff in all sense of the word. She humped her mare's warm insides like her life depended on it and as she reached her first climax of many she let out a moan and felt a wash of heat cover Fluttershy's warm depths.

She was a quick shooter in all things and speedy orgasms were just Dash's norm. She moaned as the first of many orgasms hit her. The first of many orgasms that stimulated growth. . .

Author's Note

Written/ Edited from December 2021-January 2024