Definitions by _OMEGA_

mfcsb 

Motherfucking Cocksucking Bitch or Motherfucking Cocksucking Bastard.

Flat out one of the best ways to make fun of someone. It means exactly what it stands for.
Developed by myself.

Dude1: Yo, dude, it looks like u put some weight on!

Dude2: Bull shit, you MFCSB!

mfcsb by _OMEGA_ September 8, 2008