Assbanter is the bantering with someone you consider to be an ass at the time. It's a form of dialog that may be considered passive aggressive, or argumentative in nature.
It can be an exchange of light, playful, teasing remarks; or may be be good-natured raillery. It may also be a tolerant form of dialog where each person strives to be the bigger ass.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).