Like a Sex Machine
As Rarity practiced her newfound powers in front of the mirror, she was amazed at how easy it was. All she had to was picture a pony in her mind, concentrate a little, and then after a little burst of green fire there it was in the mirror. She ran her hooves over her body yet again. Even she couldn't tell that there was anything different, that underneath her coat was dirty dark fur and a few moth eaten appendages.
Oh certainly she had been a little shocked upon waking up and having the body of a changeling, but as she sat in front of her mirror, cycling through as many different ponies as she could bring to mind, each disguise as perfect as the last, she really couldn't find a reason to be bothered by it at all.
She returned her appearance to her usual pristine state, and she headed out of her door with one thought on her mind…
Who was she going to bang first?
"Knock, knock, anyone home?"
"Oh hi Rarity! What brings you to the library today?"
"Oh, nothing much… is Spike around?"
"No, he left to help Pinkie with some baking. Their oven is on the fritz or something."
"Perfect." Rarity sauntered in, quietly locking the door behind her. "I was just wondering Twilight, silly question, what would your perfect stallion be like?"
"Well, gee, I never really thought about it…" Twilight calmly continued shelving books. "I guess I'd want them to be smart, sophisticated, self-sufficient, but still capable of appreciating all the time we spent together..."
Never thought about it my left hoof… Rarity chuckled to herself.
"Mhm, and what about… physically?"
Twilight blushed a little. "Uh, what's with the quiz Rarity?"
"Oh come on Twilight, humor me a little; a perfect stallion walks in your door and offers to have sex with you, no strings attached. What does he look like…?"
Twilight was really blushing now, although she continued shelving books in a rather futile attempt to hide her embarrassment.
"I uh… really never thought about it… much…"
"Maybe he looks like your brother? The big, strong, powerful type? Ooh, he looks exactly like your brother? You naughty girl you…"
"What!? Ew, no."
"Maybe he's the petite type then? Sauve, nicely dressed. He doesn't work out, but he's so charismatic and well put together that it doesn't matter?"
"Or maybe you can split the difference, and he's built like Big Mac… We've all though about him you know Twilight…"
"Ok… Rarity, you're starting to creep me out a little…" Twilight finally turned around, but instead of Rarity there was large, well-built stallion waiting for her, built like Shining Armor but wearing an impeccable suit and tie.
"Rarity, what the…!?"
A curtain of green fire flared around her, and Rarity slowly shrunk down until she was your average-sized colt.
"I don't…" And then it dawned on her. "Green fire…"
"Yep, I'm a changeling now."
"Rarity, how in Celestia did this happen!?"
"I honestly have no idea, just woke up like this."
"We have to get you some help!"
"What for Twilight?" Rarity shifted her appearance again, and again. "I can look however I like, and I'm still the same pony as ever." Rarity had cycled through about half the town's stallions by now, and some of them had clearly gotten Twilight interested. "I'm just a little hornier than usual is all. Guess that Chrysalis wasn't joking about feeding on love…" She cycled through Big Mac, and Shining Armor, and a dozen others, Twilight merely sitting there.
"Just think Twilight, anypony you want. Right here, right now. I mean, I know you are a virgin, but I'll be gentle, I promise."
"What, I'm not a v-virgin…"
Rarity let out one of her trademark condescending laughs.
"Oh sure you aren't. Ooh, maybe you like mares then?" Rarity started going through all of their friends, the mayor… "Or maybe you have a mentor, big sister thing going on with Celestia?" She towered over Twilight for a moment as she changed disguises again. "Or did you get a crush on Princess Luna during Nightmare Night?" The blue light playing across Twilight's face made Rarity hornier than ever. "Come on, anypony you want, right here, right now, it's just that easy. I could even be myself if you like." She returned to her normal appearance, and reached in to caress Twilight's cheek.
Twilight stood there contemplating for a moment, but as a virgin nerd, she never really stood a chance.
"Ok… You know what, fine. I want Pinkie Pie, but as a stallion, and with Celestia's manecut."
Rarity chuckled again. "Oh you virgins really do spend far too much time on the ponynet…" She complied easily though, and as stallion!Pinkie swept her rainbow mane out of her face and approached Twilight's body, Twilight secretly thought to herself…
Outside the library Chrysalis waited patiently on a cloud, disguised as some pegasi or other. Surely it could not take this long to corrupt somepony and turn them into a changeling? She'd seen plays that took less time than this!
Suddenly she heard the sound of creaking wood and moaning inside. Yes, finally some fisticuffs and shoving ponies into cocoons. Took that white derp long enough.
She floated down to a window, and as she gazed inside, she promptly realized that this wasn't a proper mind rape and corruption. And was that a pink stallion… And against the bookshelf? Man they were really going at it. Several of the books had already been knocked out of the wall. Suddenly struck with modesty, she covered her face with a hoof and flew out of sight.
The banging continued, in every sense of the word, for quite some time, the moans from both ponies varying in volume as they changed speed, direction, and location. By the time the second hour had passed Chrysalis could only sit there and facepalm repeatedly.
"This is not what I had in mind at ALL…"
Finally, after who knows how long, Rarity emerged from the building, sweaty and limping slightly.
"Well, that was fun, now who should I do next… I bet Fluttershy has some pretty kinky tastes, but Rainbow Dash we might be able to do it in mid-air..!"
Rarity walked off, and as Queen Chrysalis watched her go and noted the distinctly non-changeling, though quite exhausted Twilight Sparkle, she could only feel a mixture of surprise and confusion.
"I really need to think out my plans more carefully next time…"