13F 

Goes by many names
•Forward Observer

•Fister

•Papi Chulo

The best and only job in the United States Military.

Not Infantry and not gay was Artillery.

The 13F brings the motherfucking pain

EYES OF DEATH

Fister:"Hey girl I'm an airborne fister"
Your mother:"A 13F! Drop your pants I'm about to suck the cheese off of your dick"

13F by Eyes Of Death May 22, 2017

13/f/cali 

A response to the chatspeak phrase asl, usually used when the speaker is actually much older and male, and attempting to deceive the person he is chatting with, in order to put them in a position where they may be surprised. Or perhaps the speaker is just turned on by pretending to be a girl on the internet.

Person 1: hi asl?
Person 2: 13/f/cali u?
Person 1: 14/m/nj wanna cyber?
Person 2: k
Person 1: i take off your top
Person 2: I whip out my 14-inch meat stick and smack you with it.
Person 1: wut

13/f/cali by Jack Hoes March 2, 2010

13Fister

inserting all fingers including your penis into a vagina.

that chick was so loose i gave her a 13 fister.

13Fister by ocp February 1, 2004