"Turn into an asian girl, someone hot."
Your girlfriend smiles and rides you faster, hips rocking as you thrust into her from below. Her hair darkens as she flicks it back behind her and she begins to feel lighter as she loses a couple inches of height. She moans and looks down at you as her facial features subtly shift to look more asian. She lets you pull her hips down and takes your cock to the hilt, squeezing wet and warm as you stretch her tight pussy.
You look up and recognize her face now - she looks just like her friend Kanna, a diminutive, dark-haired beauty of Japanese descent. Kanna is someone you've always admired for her looks and talent as a gymnast, but you've never spent much time with her outside of class. Now you're fucking her. Or at least you're fucking the duplicate of her that your girlfriend has become, and it feels amazing.
She writhes on top of you as the new sensations of being fucked in this different body push her to orgasm. You follow immediately and spray hot cum deep into her ready pussy.
"I have an idea..." she says. Making a call on her phone, she has a brief conversation with someone who you realize is probably the real Kanna. Your Kanna-girlfriend finishes her conversation and turns back to you.
"She'll drop by later. I invited her over."
In the meantime...