You were the horny brother who liked to peek at his step sister as she explored her body. It's not out of the question that she's thinking about how your cock is going to enter her tight pussy and fuck her hard right on this bed. She is getting wet and blushing from those dirty thoughts. It's not right. But right now she's rubbing against the pillow, imagining your face. Maybe she'll decide to confess her fantasies to you at some point, but for now she's rubbing the pillow and moaning and you're watching her and so close to cumming