Rainbow Dash flew around the library, forming a small vortex of air that lifted up all the dirt and dust from the bookshelves that cluttered the library. She began to manipulate the funnel into floating outside through the open window, carrying the grime with it. After a few moments she came back inside and shut the window behind her, glancing around the room to make sure the rest of the doors and windows were secure as well.
"Thanks again for helping me clean up the library Rainbow. With spike gone, it would have taken me all day!" Twilight said as she placed the last book off the freshly dusted shelf.
Rainbow Dash waved her hoof at Twilight, "Yeah, yeah, just don't forget…" she let out an almost evil grin, "You promised that we would do whatever I wanted to do once we finished."
The smile made Twilight feel uncomfortable, "That's true, but you still haven't even told me what it is you want to do."
"Well I had to wait until we finished cleaning first, or with you being such a goody four-hooves you'd never agree with it." Rainbow Dash let out a chuckle, "But now that we are done, you can't back out."
Twilight's felt even more worried now, "Um… Okay, well what is it?"
Rainbow Dash thought for a moment, trying to find the best way to ask this without frightening her friend off, "Twilight… Have you ever been with a mare?" she asked clumsily.
"What?" Embarrassed and hoping she misunderstood, Twilight slowly backed off into a corner, "W-what do you mean?"
"Well, what I want to do…" Rainbow Dash smiled mischievously again, "Is you!" she said pointing her blue hoof at Twilight.
"Rainbow, are you asking me…" Twilight's sentence was interrupted by a silent nod from the blue Pegasus. She let out a nervous laugh, "Rainbow, come on… I know I promised… But not that!"
Rainbow trotted closer, "Twilight, stop being such a hoof in the mud, it'll be fun!"
"But Rainbow!" Twilight protested.
"But you promised!" Rainbow Dash whined before letting out a sigh, "Relax Twilight! I'll tell you what, why don't I start us off, and if things get to uncomfortable for you, we'll stop, but I promise you, it'll be fun!"
Twilight stood there awkwardly as the Pegasus continued to approach her. "Well… okay…" she said, disbelieving that she actually just agreed to go through with this.
Rainbow Dash caressed the purple unicorn's lips with her own, gently stroking smooth and enticing circular motions on the pony's cutie mark. Twilight Sparkle tried to back away but her companion's touch hypnotized her into continuing and soon she permitted the other's tongue access onto her own. Rainbow kept the lock of their passionate embrace as she lightly pushed Twilight onto the library's wooden floor.
The events had now gone far past what Twilight Sparkle had originally intended, but she no longer cared. Her lustful thoughts had completely overtaken her senses and they continued on. Her cheeks turned from their deep lavender to a bright red as she found herself slowly separating her legs. Rainbow Dash broke the kiss, grinning as she looked down at the newly revealed region. She trailed her tongue from Twilight's lips, down to her neck, then her chest, finally reaching her flank giving the nub soft playful nudges.
Twilight let out quiet moans of pleasure as they surged through, her hips soon starting to buck upward uncontrollably, thrusting her moistening regions into her partner's lips. Rainbow responded by securing Twilight onto the floor and diving her muzzle into the damp purple flesh, forcing even louder moans to escape Twilight's mouth. Her body was no longer listening to her, of their own free will her hooves grabbed at the multi-colored mane, pushing the pony's head deeper.
Rainbow Dash lavishly licked at the sweet nectar that seeped from Twilight's marehood, the intoxicating aroma building up, causing a tingling of her own as the fluids began to build up. Twilight seemed to be able to sense Rainbow's continuously growing arousal. She pulled her hooves on the rainbow mane, forcing the Pegasus to rotate until her own flank until just inches above Twilight's mouth.
Twilight found that she was unsure of what to do now, so she stared nervously. Rainbow Dash noticed the hesitation and lowered her knees, placing her almost dripping slit onto Twilight's face. The powerful scent that flowed into her nostrils removed the paralysis in her mind and she slowly rubbed her snout upward. As Twilight did this, Rainbow Dash's knees wobbled. Taking this as a sign of approval, she took one of her hooves and started to rub Rainbow's hood as she licked timidly at the opening.
The lower halves of Rainbow Dash's legs gave out completely and she collapsed onto her knees, she tried hard to bring the same pleasures to Twilight, but the unicorn's growing boldness stopped her, the speed and ferocity at which she stroked Rainbow increasing with every passing second, a swelling rapidly beginning to form inside Rainbow Dash.
"Twi…light…" Rainbow Dash moaned in between her heavy breaths as she tried to steady herself.
Rainbow Dash bit down hard onto her arm to suppress her loudening moans and within a few more seconds the building pleasure exploded, releasing wave after wave of ecstasy, her muscles began to spasm, and her hips pressed down hard into Twilight's snout, her body trying to scrounge every last bit of pleasure it could as the sensations shot through her body.
The sight of Rainbow Dash riding out the emotions only made her own desires hungrier, "Rainbow…" she whispered, delicately scraping her hoof against the multi-colored lightning bolt. Rainbow Dash's mind finally returned to the moment and she stroked her tongue in fast spiraling motions.
Twilight's eyes rolled as the sensations intensified and was unable to hold herself together anymore, "Rainbow!" she nearly screamed while her nerves fired off clusters of pure bliss. Rainbow Dash rolled onto her back off to the unicorn's side, the two panted heavily while their bodies calmed themselves.
Twilight began to let out an uncontrollable giggle and soon Rainbow Dash joined in, "I… told you… that… it'd be… fun!"