This is a typical Chineseslang, which is the initials for “cào nǐ mā bī” which means fuck ur mom’s vagina. Often used in curses for online/real life arguments.
Acronym of the Chinese swear "Cao Ni Ma Bi". Literally it translates to "Fuck Your Mother's Pussy", which means (I) (will)/(want) fuck your mother or I'm your dad.
Unlike the English word of "motherfucker", which suggests incest of the object person, an user of "CNMB" shames others by flaunting itself as a (powerful) rapist/conqueror.
Ruler of Lake Titicaca. Rumored to have a bunghole that gets very angry if it does not receive toilet paper. Cornholio the Great is often seen walking around with his shirt over his head and his hands in the air, chanting songs about his power, and his bunghole.
"I am Cornholio! You do not want to face the wrath of my bunghole, for I need TP!"
Butthead: Shut up, Beavis! (uh huh huh huh)
Beavis: Um, okay. (heh heh heh heh).