An action in which the index finger (on either the left or right hand) is discreetly inserted into the rectum (batty *as the Jamaicans call the rectum*).
Jax and Blade were making out in the car, when Jax slipped Blade a quick batty finger.
A giant, three finger pinch of snuff usually taken by someone who comes up and asks to bum a pinch off of you. He'll come up and ask, then take half your can in a single pinch.
Koby: "Hey man, can I get a pinch of snuff from you?"
Steve: "Yeah, but don't be takin' no three finger fatty bo batty."