shit piston
A faggot's cock. It is continually going in and out compressing shit until it finally fires
Grass doesnt grow on a busy street. That poof has a bald arse because he is constantly being thrashed by a shit piston
Shit-piston
When your going anal with a bitch and she shits while your dicks in her ass forcing it back out like a piston.
I was with my hoe last night and while we were doing it she pulled a shit-piston.