Definitions by Professor Big Penis

You're Slapping My Cock 

A phrase or expression used to communicate that you think that somebody is lying or "pulling your leg." It basically means that you think somebody is feeding you a pile of bullshit.

Greg: Hey, I won the megamillions lotto today.

Michael: No way, you're slapping my cock.

You're Slapping My Cock by Professor Big Penis April 26, 2010