Jenny from E&M always does that during a normal session.
TBH, I never thought anyone else would find that as a turn on, ie, a fully clothed lady straddled on your back, the rocking motion, with her goodies pressing down.
I don’t think she even realizes how much it turns me on, she does it due to her size and it allows good access to really work parts of your back and shoulders.
Just wished she would do it when I’m face up, but you know, she’s not that kind of girl.