also "sock buddies," these are socks used for self gratification, often turning serial masturbators into serial launderers.
Mom said she isn't going to wash my clothes anymore because 90% of my hamper is filled with buddy socks.
The act of masturbating and before your final climax you throw a sock over your penis to capture all of your "Ingredients". Also very washable and easy to conceal...
Jenna: Dude, your socks always look kinda crusty what's the deal?
Me: Oh that's just my sock buddy. No biggie!