When you devour a box of Doritos Locos Tacos and don't lick your fingers. Then you finger pop your girlfriends recently contaminated butt hole (She has to have just pinched a loaf).
Tim: Man, after I was finished the 12 pack taco box from Taco Bell, I then threw my hand down my slam-piece's pants and got my cheesy fingers in her recently packed asshole.
Finger pop is the act of popping your finger into a woman's snatch. It is employed by teens on a "car date" or by anyone who is trying to gain entry to the vagina. Finger popping is begun with the FINGER POP. It is also utilized to get the initial wetness and odor of a snatch.