(From SE Asian 'New English'.) When one's offer of help has been rebuffed, to take offence and thereupon actively endeavour to worsen a situation (out of spite).
I tried to help Brian out, but he was just really rude to me. So I decided to break my finger (off) in his butt.
If he doesn't appreciate all my advice and hard work, I will just break my finger (off) in his butt.
back in medieval days ( horsez and shit) when english invaders captured british archers they would cut off thier middle finger so they were unable to sling arrows. British archers on top of castles would stick up thier middle fingers to the english as a sort of "havn't got me yet sad fuckers!!!" so now it continues as a "fuck you" in europe and the US