During sex in the missionary position you put your fingers in the females mouth and clasp the jaw.
You then use this purchase as a holding point to pound away at your lucky partner.
Can also be done while going at it doggy style. Making it the "Rear Mandible Pound"
Guy 1: So you get lucky with that girl last night.
Guy 2: Man, she was a filthy bitch. Made me mandible pound her. Then said she liked to be choked out.
Guy 1: Sweet.
Guy 2: Yeah. So then I switched to the Rear Mandible Pound for more leverage.