Much more subtle than fuck you
or go to hell
, but with all the impact. It is the abbreviated imperative for, "You should get bent over, so someone can sodomize you on Christmas!" Used in reply to outrageous requests...
Spouse: "Honey, could you and your friends please quiet down? I'm trying to speak with mother about the baby shower."
Other Spouse: "Hey bee-atch, get bent! Can't you see that me and my homies are watching the game? And tell that old hag to suck my dick
while you're at it?"