Cardboard Sock 

(n) A Forgotten or misplaced aid for mopping up of excess semen after masturbation / wanking / 5 knuckle shuffle.

Usually under bed for sometime leaving thick, hard casing around item.

"Watched that Roco Sex trainer IX last night...blew up good stlye...
Luckily I found a cardboard sock from last time under the bed"

Cardboard Sock by Zig Ziggy Treat Teeth April 19, 2009

Cardboard Socks 

When a person is having a masturbation session, they are about to blow their load, but they haven't got something to unload into, they pick up a dirty sock and blow the load into it. They forget it's lying there for weeks, and the cum makes the sock harden like cardboard.

Tom: Dude, what is up with that smelly sock?

Jeffrey: Dude, I was lazy, I blew my big load into that sock last week and it's like cardboard now.

Tom: Cardboard socks!

Cardboard Socks by PulsarIrish November 13, 2007