This is when you are having a healthy discord with a friend and just as you think you have them on their heels, the adversary brings something up that though technically has something to do with the subject at hand, is just arbitrary enough to completely throw you off of the original argument. This mixed with the opponent's ability to speak at an alarmingly fast pace will cause you to completely forget your best point and therefore lose the battle.

A pubic hair piece. A toupee for the pubic area/genitals. In the 1700’s when mercury was used to treat sexually transmitted diseases (Gonorrhea or Syphilis) one of the side effects was the loss of pubic hair. To disguise this condition, that was not cured by mercury, a Merkin was employed.

The act of copying, mimicing, a 'funny' or humerous, action by a friend. Going over the top, with this action, either causing damage, or getting the whole group in trouble.
This is a bad social action. In order to pull a correct Howard, you have to deny the Howard itself. Thus blame someone else for the trouble, and/or damage caused
Basically; a fuck up.