A combination of the words "bro," and "obligation," used in such a manner to mean that it is a "bro's obligation."
Come on man, Jerry just got dumped. You know it's our brobligation to make him forget this night by giving him excessive amounts of alcohol, and/or taking him to the strip club!
Portmonteau of "Bro" and "Obligation". If you are bros with someone, no matter how shitty his band is or how mind-numbing his poetry is, you are obligated to be his number one fan. Or, you know, decide to take some time off from each other while you consider new bros that might be a better match for each of you.
"Dude, you read my book yet?"
"Naw man, haven't had the time."
"You got to make the time dogg. You've got a brobligation to fulfill!"
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).