From Urban Dictionary:
April 20, 2008 Urban Word of the Day
(slang verb) To keep something all for oneself, thus depriving anyone else of having any. A slang term derived from the last name of famous actor Humphrey Bogart because he often kept a cigarette in the corner of his mouth, seemingly never actually drawing on it or smoking it. Often used with weed or joints but can be applied to anything.
Hey, man, don't bogart that joint!