An ancient Chinese kung fu move which involves a male or a female (hopefully not) whipping out their dick and using it to block a karate chop, hence the name Cock Block. It has the potential to hurt the owner of the dick, but usually ends the fight with the owner of the cock being victorious. This is due to the fact that the other fighter is afraid (usually) of touching the dick, because they don't want to become gay by doing so. If you're fighting a girl.... um i guess you're screwed
Dude 1: Dude I pulled a cock block last night in a fight!
Dude 2: Dude, that's gay.