Top definition
When someone punches you in the asshole. Not fisting, being buttercupped is not meant to be sexual in anyway. Only the pains of Satan are intended when someone buttercups another.
Jason: Dude why the fuck did you just buttercup me?!?

Michael: I buttercuped you because you stole my wallet you fuck!
by TtEeBbOoWw15 August 17, 2016
Happy St. Patties Day!