The act of forcing a man's penis into a woman's inner cheek lining. As the cheek reaches it's maximum extension it bounces back
Jean and Rick played trampoline in the car during their lunch hour.
A variation of the trampoline, whereas the mouth of the participating female is defecated in and the male participant then proceeds to insert his penis into the inner cheek area in a trampoline fashion.
In a flash, Rick was performing the Cincinnati trampoline with Jean at the drive in theatre.