v. - To intentionally collect shit (feces, including
dingleberries, butt sweat, etc.) onto one's finger (commonly
the middle finger, being the longest) and, upon exiting the bathroom or other relief area, then seek out a
particularly intolerant, insufferable, jerky, arrogant, drunk, or otherwise undesirable person (see also: shithead) and proceed to approach them from behind (or sneak up on them), grab them by the face, and stick the shit-greased finger past their lips and into their gums (but not beyond, so as not to get bitten).
This act is one of extreme boldness, bravery & conviction, and should be reserved only for the worst offenders and/or situations where one can escape quickly and with ease.
"Once you figure out what it is, then you realize someone did it on purpose."
Ned: Jesus, that guy is an asshole.
Larry: He might just be drunk.
Ned: No, he's still a tremendous asshole, he's been like that the whole concert. You should've heard him when we came in, too.
Larry: Is it bothering you that much? Then fuck it, give him a shitfinger, right in the gums.
I've got your back.
Ned: Yeah. Man, I never do that, but that
fucking guy deserves it.
Hold my beer, I'm going to hit the port-a-potty and will be right back.