Means that someone is so intoxicated (usually with alcahol) that they lose control over their bodily functions and deficate themselves.
Me : Oh my god did you see Gordon at the party last night, the guy shit himself after being refused at the bar!
Friend : Yeh, he was shit wankered alright, what a total idiot.
Friend : Yeh, he was shit wankered alright, what a total idiot.
by Steven Bell April 8, 2008