Control Group

by Baron Von Clop

Rating: mature
Tags: Slice of Life, Romance
Length: 997

When Twilight discovers that nopony has written an accurate, up-to-date book on pegasus metabolism, she seeks to right this grave injustice to the literary world. The only thing worse than no book is a wrong book.

When Twilight discovers that nopony has written an accurate, up-to-date book on pegasus metabolism, she seeks to right this grave injustice to the literary world. The only thing worse than no book is a wrong book, and it just so happens that Rainbow Dash is the perfect candidate to help her with this experiment.

Story contains Twidash shipping, graphic sex and language.

Co-authored by Q.T. Marx.

Cover art by Stonershy

Published 1970-01-01 00:00:00 UTC
Last updated 2013-01-31 09:09:05 UTC

Prologue

        Rainbow Dash moaned out loud as the mare on top bucked her hard again, feeling her end of the double-ended phallus slip deeper into her, quenching the fire that was building up between her legs from the moment she entered the room with the unicorn. The back of her head dug into the pillow behind her harder as she was slammed against it, a wet shlick reaching her ears as the mare came in for another thrust. Their respective blue coats were matted all along their thighs and belly where their juices mingled with each others and their bodies rubbed, soaking down to their skin and cooling in the bedroom’s cool air.

        Rainbow didn’t even remember having been thrown onto her back, but in the end it didn’t matter. Her partner was more than capable of working the tool that was currently lodged deep within both of them, the unicorn bucking her hips in a swirling motion and stroking her inner walls with the tip of the dildo. Another hard moan rose up out of Dash, matching the intensity of her partner’s wild groaning as yet another slam came down and thrust the fake stallionhood into her with the same force as the others.

        Dash mumbled her name incoherently, more fumbling for words as she attempted to work out some way to praise the mare currently on the giving end of the best sex she’d experienced in years. She wasn’t even moving anymore, just allowing her unicorn partner to work how she wanted, the nature of the toy between their legs pleasuring both of them even with one being lazy. Finally, Rainbow Dash was able to moan out a long sentence, the pure pleasure shooting through her mind making the words fuzzy to herself.

        The rocking and bucking slowed down, like a roller coaster sliding into its dock at the end of the ride, but Dash specifically noticed that her partner was still sitting up, muscles tense as could be, and neither of them had reached climax as far as she could tell. Her eyes cracked open, floating down to glance at the equally blue mare atop of her - just in time to see the hoof.

        Dash’s head shot back against the pillow, recoiling from the blow that landed directly on her cheek. She reflexively pulled a foreleg up to protect her face from a repeat attack, but instead was greeted by the unpleasant sensation of her partner rolling to the side and attempting to unmount her. “C-Colgate, what are you doing? That hurt!” Dash shouted, pulling her foreleg back to rub at her cheek with a hoof. “I’m not into that kind of thing!”

        “Applejack? You called me Applejack!” Colgate screamed in response, cheeks glowing a bright red out of sheer anger from the extremely uncouth mix-up. “Are you kidding me? If all you’re going to do is fantasize about other mares while we’re fucking, I’m so not interested!” Colgate caught her rear hooves against the sheets and pulled herself straight up. The phallus slid out of her marehood and slapped weakly against Dash’s belly as it went limp, the other end still lodged deep into her own privates, motionless.

        “Oh, come on, Colgate! It was a mistake! W-wait, come back,” Dash whined. She sat up in bed, the rubber toy flopping forward, reaching a hoof out towards the blue unicorn. Colgate simply slapped the hoof away as she stepped off of the bed and trotted towards the door, leaving Dash in her extremely compromising situation. “We aren’t done yet!”

        “Oh, yes we are. You’re an asshole, Rainbow Dash,” Colgate said as she tossed the door to the inn bedroom open with a faint blue glow, stepping out of the door and slamming it shut behind her.

        “Ffffuck,” Dash groaned, flopping back against the bed. She pounded a hoof against the sheets, the waves of motion rolling through the springs and causing her to bounce slightly. “Stupid sexy Applejack.”

        With a heavy sigh, Dash lifted a foreleg and reached for the dildo still clenched between her lower lips, gripping it in an ankle as she slowly slid it forward and back. At least this wasn’t going to up and leave her any time soon over such a small mistake - toys didn’t care what name you called them, and that was how Dash liked it.

        Just as Dash managed to barely get herself back into the mood, the door swung open, and a still just as angry Colgate stood in the doorway. Wordlessly, her horn sparked and began to glow, wrapping the exposed end of the rubber toy in a light blue haze, and Dash fought to keep it between her legs. Both forelegs shot out and grabbed hold of the toy, Dash groaning with exertion as she wrestled with her disgruntled one-night-stand over the fake penis.

        Magic eventually won, however, Dash’s hooves slipping on the natural lubrication covering the rubber cock, and the dildo floated limp in the air. “And this is mine!” Colgate yelled, turning her back to the room. Dash narrowly avoided the toy as it swung through the air, aiming for her head, before it followed the angry unicorn out of the room.

        With an angry, incoherent shout, Dash grabbed hold of the bed’s pillow and flung it out the door. It smacked against the wall in the hallway, achieving absolutely nothing. It laid still on the floor for a few seconds before it, too, was gripped in the same blue glow and floated down the hallway. “Fine! Take the pillow, too. Get out of here, Colgate!” Dash shouted, attempting to be the one in charge of her departure, though she wasn’t sure who she was trying to fool.

        She threw herself against the bed, wiping at the corners of her eyes with a foreleg before shaking her head.

        “Fuck this,” Dash said to nopony in particular, rolling over onto her side and burying her face into the cover sheets below.