Yours, Etc.: Origins and Uses of 8 Sign-Offs
1969, "to keep a joint in your mouth," dangling from the lip like Humphrey Bogart's cigarette in the old movies, instead of passing it on. First attested in "Easy Rider." The word was also used 1960s with notions of "get something by intimidation, be a tough guy" (again with reference to the actor and the characters he typically played). In old drinking slang, Captain Cork was "a man slow in passing the bottle."
[1960s+ Black; fr the tough roles played in films by Humphrey Bogart]