Could be a reference to an annoying or self absorbed person who could either be bragging far too much or putting others down in a manner that is unacceptable.
This could also be used as a cuss
word for when you may be in trouble, angered at something that has happened at that immediate moment, or are in the process of being completely screwed
. This is similar to the meme "FFFUUUU
James: Hey, I got an A+ on the test and you got a D. You fail! Haha!
Cory: You buttfuck
Tim: I'm being mauled by the zombies! HEELP!
Michael: I'm at the other side of the map, I can't help you!