cum knock 

When you knock on the door of an unsuspecting individual then cum on them when they open it

She blue balled me so I cum knocked her.

cum knock by ZaneyDreynor January 14, 2017

I'm gonna cum to your house and knock knock on the back door 

A dirty way of saying surprise butt-sex.

1.Waffles: Hey Dwarfo, I'm gonna cum to your house and knock knock on the back door. If you don't answer, I'm gonna bang bang!

Dwarfo: Yeep! I hope it isn't too surprise!

2. What rapists say to little kids when they are gonna butt-rape them.

I'm gonna cum to your house and knock knock on the back door by Dr. Dirty October 9, 2008

cum knocker

when whoever is eating cum knocks it back in their throat for a swallow.

That bitch I was with swalloed shes a motherfukin' cum knocker.

cum knocker by REN12335 March 1, 2009