The act of reaching your hand into your rectum and covering it with shit. Then using the shit covered hand to masturbate. The shit will act as a lubricant
Joe: I cummed to the roof whe I finally decided to Shitsturbate!
Paul: I told you!
Joe: Yeah, poop is good lube.
Paul: I told you!
Joe: Yeah, poop is good lube.
by Topazoo November 29, 2009