When a woman performs a sexualact and after (or during) said act calculates the relative worth of act. Often, this is followed by demands for remuneration from the recipient of act.
Damn, Tiffany gave me the hottest blowjob last night... then she ruined it by doing whore math and making me take her out to dinner afterward instead of just going to sleep.
when you're holding up your phone and making faces at it, as though you are taking a selfie, but you're really taking a picture of the person across from you or the wall or anything else that seems interesting but you don't want to be caught dead taking a picture of.
This action is often made more convincing by wiggling the eyebrows or opening the mouth, to pretend you're trying to get a Snapchat filter to work.