Remember, kids: Steroids are bad!
Rainbow Dash's third reread of the latest Daring Do novel was interrupted by a knock at the door. Sighing, she set aside her book, floated downstairs, and flung open the door. On the other side was Bulk Biceps.
"Oh, hi Bulk Biceps. What's up?"
"P IS FOR RAINBOW DASH!" Bulk Biceps declared loudly, the force of his yell blowing back Rainbow Dash's mane.
Rainbow Dash blinked. "Uhhh...no, it isn't," she said. "My name starts with an R, and--"
"P IS FOR RAINBOW DASH!" Bulk Biceps bellowed again, rearing. As he did so, Rainbow Dash could just see a tiny, stunted little pecker unsheath itself. Before she knew what was happening, a powerful stream of urine caught her right in the face.
"GAH!" Rainbow Dash cried, spitting and shaking herself. "WHAT THE HAY?!"
"P IS FOR RAINBOW DASH!" Bulk Biceps declared one final time, before flying slowly away.
Rainbow Dash blinked, mane dripping urine on her living room rug. "What...just happened?" Grimacing, she flew up to her bathroom to take a nice, long bath.
* * * * *
Rainbow Dash lay upon a soft, puffy cloud, catching an afternoon nap after a hard morning of cloud busting. A thunderstorm from the Everfree Forest had wandered into Ponyville, and it had taken most of the morning to dissipate it. Hard work deserved a reward, and Rainbow Dash's favorite reward (besides praise for her awesomeness) was a peaceful cloud nap under the warm sun.
Eyes closed, she basked in the slightly muggy afternoon warmth. The comforting embrace of sleep had just begun to claim her, when...
"P IS FOR RAINBOW DASH!"
A hot golden rain splashed down on the dozing mare. Spluttering, Rainbow Dash abandoned cloud and zipped out of the way of the impromptu disgusting shower. "BULK BICEPS!" she growled. She zipped up into the sky, confronting the overmuscled stallion, hooves on her hips. "What. Is. WRONG WITH YOU?!"
"P IS FOR RAINBOW DASH!"
"NO, IT IS NOT! Now CUT IT OUT!" Rainbow Dash slammed her hooves into Bulk Biceps' muzzle to drive her point home, then flew off to her cloud house for another long bath.
* * * * *
Rainbow Dash met up with her friends for a nice brunch. Applejack had provided apple turnovers (she wanted to bring apple brown betties, but everypony was sick of them and politely asked her to bring something else), Rarity had bought some light, airy, flaky croissants, and Pinkie Pie had arrived with a large box of delicious Swiss cake rolls.
As everypony loaded up plates with treats, Rarity brought out a stack of paper cups. "Lemonade or coffee?" she asked Rainbow Dash.
Rainbow Dash shuddered. "Coffee. Please. I don't even wanna see lemonade right now."
Twilight Sparkle blinked. "Is something wrong, Rainbow Dash?"
"No, nothing's wrong!" Rainbow Dash said hastily. "I'm just not crazy for anything yellow right now."
"But...I'm yellow," Fluttershy said sadly.
"I mean anything liquid and yellow," Rainbow Dash added.
Rarity raised an eyebrow. "Are you having...problems, Rainbow Dash?" she asked.
"Uhh, well..." Rainbow Dash rubbed her neck with a hoof. "It's...how do I expla--"
"P IS FOR RAINBOW DASH!"
"GAAAH!" Rainbow Dash bolted into the air, a split second before a stream of pee strafed the ground where she'd been sitting. The others blinked.
"Whut th' heck?" Applejack asked.
Rarity cringed. "Is...is that...?"
"It is," Twilight Sparkle said, nose wrinkling. She looked up in the sky, and her eyes widened. "What...the..."
Up above, Rainbow Dash was zig-zagging through the sky. Every few seconds, Bulk Biceps appeared in her path, moving impossibly fast--especially given his pathetic speed records at the relay qualifier. Every time he stopped, he unleashed a blast of urine at Rainbow Dash, who rolled out of the way and flew off, Bulk Biceps giving chase.
On the ground, five mares and a dragon looked around at one another, blinking.
"Oooookay," Twilight Sparkle said, frowning. "What was THAT all about?"
* * * * *
Rainbow Dash had flown all the way to Cloudsdale to escape Bulk Biceps' inexplicable, single-minded determination to pee on her. Panting, she hovered in the air, eyes wary, scanning in all directions for any sign of the hulking horse.
She had less than two minutes to rest before Bulk Biceps appeared, making a beeline for Cloudsdale. Eyes wide, Rainbow Dash dove into a pool of liquid rainbow.
Five minutes passed quietly. Finally needing to breathe, Rainbow Dash leapt out of the rainbow pool, gasping for breath as her muzzle broke the surface.
"P IS FOR RAINBOW DASH!"
A drizzle of whizz pelted her, getting into her open mouth.
"GAAAAAAAAAAAAAAAH!!"
* * * * *
After three days, Rainbow Dash was becoming unhinged. There didn't seem to be any escape. No matter where she went, no matter what time of day or night, just when she thought it was over, Bulk Biceps would pop up, scream "P IS FOR RAINBOW DASH!", and try to pee on her.
"Why is he DOING this?" she moaned to Twilight Sparkle as she paced the library.
"I don't know," Twilight replied. "The only thing I know about weird sex fetishes is to stay as far away from that stallion with the big jelly jars as equinely possible."
A pounding knock shook the door. Twilight and Rainbow Dash exchanged glances. Rolling her eyes, Twilight walked over to the door and opened it.
Bulk Biceps stood on the other side. "P is for Rainbow Dash?" he asked, poking his hooves together.
Twilight sighed. "Look...Bulk Biceps...P is not for Rainbow Dash. And she's getting a little tired of you trying to pee on her all the time. And frankly...it's more than a little gross. If you don't stop trying to pee on Rainbow Dash, I'm afraid I'm going to have to banish you from Equestria. Um...I can do that, you know. Because I'm a princess."
"Oh. Okay." Bulk Biceps said. "Have a nice day." With that, he turned around and left.
Rainbow Dash stared, jaw agape. "That's it? That's all it took?"
Twilight rolled her eyes. "You didn't actually even try talking to him, did you?"
"He was PEEING ON ME! I was freaked out!"
Twilight chuckled. "Well, I'm just glad that's over..."
"You and me both..."
* * * * *
For the rest of the day, Ponyville was peaceful and quiet. The next day dawned bright and clear, and another lazy, easygoing day began in Ponyville.
The gentle bustle of everyday small-town life was...not so much shattered as it was very slightly scuffed by a quiet scream as Fluttershy flew down the street, pursued by Bulk Biceps.
"P IS FOR FLUTTERSHY!"
"No it isn't!" Fluttershy squeaked. "F is for Fluttershy! Um...not that I want F either!"
As everypony watched Fluttershy run in terror from the pee-obsessed bodybuilder, a grey pegasus turned away from the spectacle and shuffled slowly away, head hung low.
"Why can't P ever be for Derpy?"
Author's Note
I have absolutely no excuse for this. 
