A Dreadsock is a standard sock with a (metal) 40K Dreadnought inside. The Dreadsock is then used to 'beat the stupid/cheeze/beard/shit' out of people.
In general useage, "Dreadsock" is usually suggested to emphasise how stupid a situation is.
Note: it is not advisable to actually hit someone with a real Dreadsock - it can cause serious injury, and get you in a lot of trouble!
"Take one Dreadsock, and apply as many times as needed to make him stop."
This usually results in pain for the offender. This is a good thing.
However, never Dreadsock Chuck Norris, don't even think about it unless you want to have your testicles crushed. It hurts, believe me.
Player 2: Yeah, but u wayt untylz i pwn u wiv mah dubel lash Chaos army!!!
Player 1: WTF mahn?!?!
Player 2: It haz 3 Vindicatorz 2!!!
*Player 1 proceeds to Dreadsock Player 2*
Player 2: MAH FAAAAAAAAACE!!!!!! IT IZ TEH HURTZ!!!!!!!!!
Player 1: That'z wot u get 4 being a cheezey foo.
Player 2: WHYYYYYYYYYYYYYYYYY?!?!?!?!?!?!?!