aka brown sock. When a person is extremely promiscuous when it comes to anal sex they have higher odds of getting a pink sock, therefore when their bowels are so often exposed to the elements they become blackened from exposure, dragging through the dirt, etc.
That slut takes it up the ass so often you have to watch out you don't step one her (as a gay man would refer to another) black sock dragging in the dirt.
by Frostville October 20, 2007
When you lick your shit off
DUDE. I BLACK SOCKS YESTERDAY AND IT WAS GOOD
by what_you_looking_at August 11, 2011