One of the dozens of slang terms used by Beavis and Butt-head. Buttknocker could refer to
a)A homosexual, as anal sex is the only form of intercourse for gay men, or
b)An erection in somebody's ass, referring to pulling out and then tapping and wiping the semen on said ass.
Beavis: Shut up, Butt-head! I'm gonna play drums on your nads with my foot!
Butt-head: I'd like to see you try, buttknocker!
Beavis: Don't call me that, Butt-head! (Beavis kicks Butt-head in the testicles)
wqhen u indentity as an BUTT and u................. do butt things like u pee out ur butt and liekt hats ok but maybe so ee adocter abtout that i dont think thts nromal but ur a butt so............. BUTT BGN EDNER lalso asosciated with sansgender bcus sand head look a lil like a butt so we r connected thoruh stars