You give in

You hear yourself whisper "please cum in me" as Gwen breaks off the kiss, and Gwen obeys, plunging balls deep as she explodes inside you with a lustful groan and fills your womb almost to the brim. Gwen's orgasm prolongs your own, and you feel your contractions push her seed even deeper, even as your cunt milks her shaft for more. As you both recover from your climaxes you feel the warmth of Gwen's cum spreading through your lower body, almost like her seed was seeping into your body.

"So...." She pants slightly "I guess you'll have to go by Sara from now on..."

"Yes..." you whisper

"And... I'll have a cock from now on too..." she confirms

You nod your head "Sorry--" you start

"Hey don't apologize, I was the one who wanted to cum inside you. Besides, if it means I can fuck like this every day, then it's worth it."

You felt a twinge of relief. After all, you were the one who made your current reality possible, even if she was the one who made it permanent. You gasp as she finally pulls out of you, and almost immediately her excess cum spills out of your well-fucked pussy and pools onto the bed. As Gwen looks for the handcuff keys, you look down at your now permanent body.

Guess I'm like this forever now. As you stare at yourself, you imagine your belly getting rounder and rounder as your breasts get heavy and sensitive and full of milk. You imagine yourself heavily pregnant as Gwen fucks you roughly. You imagine begging her to slow down and be careful even as you cum on her cock over and over and-

"Hey, turn over." She says, snapping you back to reality. You hear a click and feel the cuffs come off.

"Erm..." she looks at the pool between your legs, slightly embarrassed at the sweaty, cum-filled mess she made of you "I'll get some new bedsheets..." and leaves her room. You manage to roll out of bed and walk unsteadily to the bathroom to shower. With your hands finally free again, you rub your sore wrists and breasts, as the warm water washes the sweat and cum away. Your breath catches as your hand slides over your nipple, surprised at how sensitive Gwen's teasing made them. Your hands go down to your crotch and find Gwen's cum still flowing copiously out of your pussy

Jesus, where does she keep it all? A few thick, white globules cling to you hand as you pull it back up to look. Just one drop of this was enough to end your manhood and Gwen pumped you with enough to soak the sheets. You give it a lick out of curiosity, and another, and then another. You sex throbs anew as you suck your fingers clean, and it isn't long until you're openly masturbating to the taste of Gwen. You feel her cum stirring around inside you as your fingers find your g-spot and tease your clit. It feels incredible. You let the water wash the rest of Gwen's excess cum away as you pleasure yourself.