When one is on the fence about an important decision, instead of "sitting on it" they "fap on it" (jerk it, rub one out, a good wank, etc.) then revisit the issue at hand with a much clearer mind and thought process. Usually pertains to issues involving bitches and hoes.
The term was coined in the famous rage comics on reddit.
Jim: Hmm I'm not sure if I should fuck my ex again. I know I'll fap on it.
* fapfapfapfapfap*
Jim: Nah fuck that bitch
Tom: Do I really need that new TV? Welp, time to fap on it.
*fapfapfapfapfapfap*
Tom: Fuck yes I need a new 60 inch plasma tv
To masturbate prior to making a decision involving women. "Fap" comes from the onomatopoeic representation of masturbation popularized on the internetvia web forums.
When one faps on it, sexual tension is released through masturbation, resulting in a mind that is clear in thought and a rational decision can be made involving women, usually sexual decisions.
Bro 1: I'm not sure I want to drop $40 tonight on drinks with Jen at the bar. I wanna fuck her, but I don't know if it's worth spending dough on her.
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.
FRIEND A: "Did you just take a stealthie of me?"
FRIEND B (turning phone around): "no I was just using snapchat's new filter, see?"