How exactly do you see this happening? Like the guy wants to pull out and cum on her and she says 'no, cum in me,' or more like she straps him down and rides until he coats her insides?
I mean, the way I see it, the guy would be hard pressed not to cum in her and cum in her quickly.
I could see her wrapping her legs around him tight so he can't pull out. Like a reverse unwanted creampie. Maybe a lost a bet concept, maybe *********...