Originally Posted by
Murlocbait
Defensive Stance is only active for Arms if you take the talent. For Prot warriors it is a passive effect, so you're right there are no more stances for Prot or Fury (and just one as a talent for Arms). I'm not currently playing so I can't say for sure, but I would think you'd just have to (at most) do the old "wait a few seconds" trick. Once the other tank taunts off you, wait a 3 or 5 count and then go nuts with a dps rotation. Obviously don't use taunt or anything until it's time. You can use an addon with threat tracker if necessary. But if you back off for just a few seconds, the other tank's taunt and rotation should give him/her enough threat that you won't be an issue until you Taunt.
Again, there could be something going on now that makes that untrue, but it's what I'd start with.