when someone dips their haemorrhoids (bum grapes) into someone else's mouth, similar to the art of tea bagging. Named 'The Julius Caesar after' the great man himself and his recognised love of grapes.
The act of having anal sex with with your bestfriend's wife or girlfriend and immediately following ejaculation screaming Et Tu Brute!!!!!!!! Extra points if done while wearing a toga, and the "hat trick" if you do all of this on March 15 ( the ides of March). In reference to William Shakespeare's Julius Caesar.
Dude, my "best friend " never paid me the 300 dollars he owed me so I tied my sheets on toga style and gave his girlfriend "The Julius Caesar"!