Inmate slang for the younger inmates just entering the systems ass hole. Basically if you're doing life you'll never see a vagina again so the next best thing is a poop vagina.
Have you seen the new white girl on the block. She sure looks fine and I bet that shitpussy is so tight she can barley keep a cigarette in there. I can't wait until I befriend her by leaving a snicker on her bed and steal that shit pussy.