look up any word, like bukkake:
An insult of medium offense, comparable to the words dick, gayboy and knobhead. Derived from the idea that the victim of the insult drinks, or chugs, feces from another's behind, or butt.
Man, you know Garry? He's such a buttchugger!

Man 1: I'll kick your face in, you knobhead!
Man 2: Just try it, buttchugger, see where that lands you.
by Advance March 08, 2013