This starts off with a guy taking a shit on the upper part of a girls back. The guy then slides in between the girls legs on his back and begins to masturbate. The chick straightens her back and the shit slides down her back and onto the masturbating mans cock. After all the shit has slid off her back she then squats over the man and pisses on the poopy dick leading to a gigantic orgasm for the man.(Assuming you like masturbating with piss and shit)
God Dammit, that fucking hooker I bought for Don's bachelor last night charged me an extra 100 bucks to give him a Rock River.
This term comes from The Rock River which runs through my hometown of Rockford, IL. It is dirty and consists mostly of the piss and shit from the Nascar hillbillies that live here and boat on it.