You Fuck Your Girlfriend in your sister's body

"I don't know, babe... Maybe this is a bit weird you act like my real sister...", you retract backwards, away from your girlfriend/sister.

"I think...like, that you should totes just fuck me already", your shapeshifting girlfriend/Sister counters with her bitchy voice as she starts to take your cock with her dainty hand, her long fingernails now tipped with black nail polish, your sister's favorite. You stopped fighting, the part of you that has always desired your beautiful, if shallow and bratty, sister, getting extremely turned on by the sight of her pulling out your dick from your pants with her small, manicured hand. You stare into her eyes, now ocean blue, completely different from your girlfriend's original eyes, yet still so similar, as she clambers on top of your dick and starts riding you. She starts moaning in her high pitched voice, and her wide hips press her now beautiful, heart shaped rear into your groin. You glide your hand across her fit stomach and her hefty D-cup breasts, making her shiver with lust.

"Yes, big bro. Fuck me like the fucking slut!" your GF/Sister screams in pleasure as she plays with her dirty blonde ponytail hairstyle, upon which you release your semen.

“OMG, that was, like, super hot, bro. You're like, the best brother.” Your girlfriend/sister says as she still sit on your lap.

"Well, whatever you say, sis... I mean... babe." Grabbing her by the ass and pulling her in for a kiss.

“So, like, what do you want to do next, bro?” your former girlfriend asks as she's kissing your face romanticly.