You decide to enter......

You decide to enter. Wondering what is causing Sarah to scream that loudly as you've seen her get her self off with her fingers,toys and what not. And never have you heard her scream as loud as this except when having sex together. You see her lying there on the bed with another woman between her legs eating her pussy.

Shocked you can only stand there and watch as she's never even hinted at les or bi behavior. But nonetheless the scene before your eyes is very erotic. You are excited and puzzled at the same time. The woman giving your girlfriend pleasure seems familiar, yet you cannot recongnize her because her face is buried in your girlfriend's pussy. While moaning your girlfriend let's out an ohhhh Stephanie! Suddenly you realize that's Sarah's year and a half younger sister.