Short for Big Bad Mother Fucker, a term most commonly used as a desirable status by insecure, angry incels as a way to assert their dominance, bang the bitches, and shoot big guns while imagining their cocks are twice as long. You know, all the things they don’t do in real life.
Brad, not Chad: When I graduate high school, I’m gonna join the army and become a BBMF!
Guy: Dude, you barely even leave your parents basement wtf
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.