"What's that?"
"Oh, you'll see," she grins. The room shimmers, and you feel weird. Like you're getting... younger? Your clothes and hers seem to turn blurry too, and you notice she seems to be growing younger too. When it stops, you're in a bedroom that looks vaguely familiar. There's a bunch of boy band posters and stuff, and you feel like you've seen it in photos or something.
You realize you're in a smart shirt and trousers, and looking at your girlfriend, you see she's wearing a white blouse and smart black skirt and tights. "Wait... is this school uniform?" you laugh. Suddenly you notice your voice is a bit higher-pitched than before.
"Yep," she grins.
"Sooo, do you have a school uniform kink you never told me about?" you tease.
"Oh, this is MUCH better," she purrs. "Do I remind you of anyone?"
Suddenly it clicks. Oh fuck... "You're... you're Jessica!" Your girlfriend has turned into the girl you had a crush on in your second year of high school.
"Yeah! And look in the mirror for who I turned you into," she says.
You get up, and recognize the face. "This is... Eddie, right?" She nods. That's the guy SHE had a crush on in second year of high school. "Are you trying to tell me you still have a big crush on that guy?" you laugh.
"Nope," she says, getting up and kissing you passionately. To your surprise, it only takes her doing that for you to get hard. "You get why I did this now? It'll be like having our first time as horny teens."
That does sound tempting...