A depraved sex act involving two individuals, for the sake of explanation we'll say a man and a woman, performing anal sex. The man begins to slowly withdraw from the woman's anus and then quickly rams his member back inside, this is followed by swift and aggressive punches to the woman's sides. The entire affair mimics the act of playing pinball.
Sorry bro, I totally just topped your high score in pinball wizard, last night with your mom. 25 times leaves a couple bruises.