Seemingly derogatory term but often used with affection. In the classic sitcom Malcolm in the Middle, the brothers call each other buttmunch but with a smile and a pat on the back. The word can also be used as a sexually suggestive term, using it on someone you would actually like to munch on your butt.
1. Reese to Malcolm: Way to go buttmunch! I'm proud of you!
2. Reese to Malcolm (pulling down his pants): Hey buttmunch, dive in!
Any person in a position of authority whom by virtue of their ass kissing abilities have elevated themselves to level where they are required to wear a cheap plastic nametag with their name on it followed by the word "Supervisor"