An ass cancel is when a male goes into give a hug to a female friend, only to cop a feel on her ass.
Named for the advanced fighting game technique of canceling an animation into another single or string of moves.
Can be one of 3 different types:
Jab - A pinch
Fierce - A grab
Strong- A slap
"Nice one, man! You totally got a fierce ass cancel on that coke bottle girl's ass!