Cock Chalk 

this is the white residue left on your clothes (usually inside your jeans) from 1-3 day old jackoff semen that you forgot to clean and now has become a chalk-like powder that kinda flakes off when you scratch it with your nail, wondering what it is...

Ernie, this cock chalk all over your clothes is out of control!!!! Please son, stop jacking off so much.

Cock Chalk by 777geez November 20, 2015

cock chalk 

What you call it when you write on something with your cock after you bone some chick on her period.

after i did lauren last night i marked her up with some cock chalk.

cock chalk by Chuck Bucket February 18, 2005

cock chalk 

the residue left around the outer edges of the lips after giving felatio

nicole was giving shawn a blow job and had some cock chalk left on the edges of her mouth

cock chalk by lakeguy March 20, 2009

Cockchalk

What the dried cum on your penis becomes if you don't clean it all off. May also be dried precum. (or a dirty cock)

I hate to wear black underwear because sometimes i have cockchalk and it marks my underwear up.

Cockchalk by agrafos April 26, 2010