When a guy's butt crack is visible when he bends over. Related to the term plummer's crack. Apparently many plummers butt cracks have been visible while working in client's homes.
Man1: Dude, cover that up!
Man2: what?
Man1: your ass crack, you're plummering something fierce.
Nickname given to bales of marijuana thrown overboard or out of airplanes. Origin is reportedly from members of the US Coast Guard in the area of Southern Florida.