A sexual act where one individual inserts a thumb into another individual's butthole and then smears the feces across the other person's throat a la Jack the Ripper. Also known as the Sweeney Turd.
Shit dog, we ate a bunch of dim sum and when we went back to the house, I gave her a Jack the Shitter before she could get on that Squatty Potty.
goes into public bathrooms and shits in urinals
ME: Hey Matthew, we are gonna have to start calling you "jack the shitter"