A maneuver commonly used in the sport of American Football where while in a dogpile a player will pull a dreadlock of an opposing player through his helmet's ear hole, and then proceed to tie it to his face mask. If the dreadknotter is especially skilled and the dreadlocks are of sufficient length, the player will be able to tie the dreadlock to the other player's belt and/or shoe laces. The real accomplishment however comes when the player is able to tie more than 1 dreadlock to any part of the other player's gear resulting in the Multi-Dreadknot, which is quite an incredible feat indeed.
Larry Fitzgerald is overrated as hell, and his hair is very dumb. I wish Aaron Ross would dreadknot that bastard the next time they're in a dogpile.