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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!
by _OMEGA_ July 22, 2006
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