Slap it down 

Term of encouragement or disparagement used by white men with small penises after a notable ribbing.

"I said 'slap it down', homie"

Slap it down by Marty February 22, 2003

slap it up, rub it down 

A type of masturbation involving a gentle slapping to stiffen the penis, followed by stroking up and down the shaft of the penis to the point of ejaculation.

When Willie is a little slow to wake up one thing you can do is slap it up, rub it down.

slap it up, rub it down by Popo4242 August 11, 2017