A test gauge process for attempting to measure a woman's willingness to engage in Anal Sex. The act consists of slyly slipping a spare digit into a woman's anus during the process of making out or intercourse. If she protests, she's unlikely to allow for anal sex. If she doesn't protest, there's a high probability that she will allow herself to be blasted in the ass.
So I was balls deep in this chick, and she was going crazy. And I dropped in a Rogue Finger, and she started bucking like a war criminal hooked up to the electric chair. So I replaced my finger with my dick and went to town. Then she went ass to mouth. What a whore.