This was made up when Mirikh was too tired to actually say the full sentence "You Fucking What Mate?" after getting offended by something someone said on Discord.
Guy 1: This guy :slight_smile: :point_up: fucked this guy :slight_smile: :point_down: in the ass
Mirikh: YFWM?
Guy 1: What?
Mirikh: YFWM > You Fucking What Mate, just made it up. You like it? You can use it if you like.
Guy 1: Wow, why so toxic.