The most humiliating act a man could ever give. Should you be the unlucky victim of a cockslap, especially when you're sleeping, the best advice is to kill yourself.
"Haha, I gave you a cockslap you when you were sleeping, and filmed it!"
to slapsomeone in the face with your half-erected dick. doing this before or after having sex it is the only secure way to avoid pregnancy and venereal diseases.