The act of finger penetration to either the vagina or anus, while from behind. This can be accomplished standing, sitting, bent-over, or preferably while she's asleep with her back to you.
While my girl is blowing me in my lap, I like to finger jack from the back to pass the time. Then I cram my fingers up both of her nostrils so that she can smell her dirty ass all day long.
by Finger Maniac March 03, 2011