The Don't Rule is a very simple meta-technique used to indicate willingness to escalate (primarily, but not only) physical scenes. It is also known as "The Rule of Don't"
If used, the don't rule is a tool for players in, for example, violent scenes. By vocally saying Don't followed by an action the player signals that that action (or similar action as that which has just been taken) is okay if the other player wants to perform it. For instance, if a player physically attacks another player, and that player says Please don't hurt me anymore!, it is made clear that further physical violence is okay. It can also be used to signify specific actions that the receiving player is okay with, as in please don't leave me here in the dark! or please don't tie me up.
Often, the more specific the action described after the word don't, the more enthusiastic the one describing it is about being subject to it.