Basically, a person who laughs at his own jokes making it less funny. Can also be used to address someone who makes a joke or points out something that is funny, but really isn't to a majority
God, the really funny mothafucka is at it again! One more joke from him and drinking potassium cyanide doesn't even sound so bad!
2. ::frog breathes:: The shiot has hit the fan, mothafuckaaaaaaa!!
3. When the fangirls claimed Orlando as their own, the girl with the gun in the back of the crowd screeched, "THE SHIOT HAS HIT THE FAN, MOTHAFUCKAAAAAAAAAA!" and shot all the fangirls.