Originally Posted by
Nikkaszal
Vigilance is your best friend.
Not only does it keep your Vengeance running, but the taunt-refresh mechanic is nifty if you're having real aggro trouble.
There's no real need for you to be constantly tanking the tentacle after the Prot Pally gets Impaled - the debuff only boosts Impale damage, meaning so long as you have aggro as the second Impale comes around, you're golden. If you keep having severe trouble holding, keep a weather eye on your DBM and taunt the tentacle right before the second Impale comes. Once it's started casting, it won't change targets. All that needs to happen is for the second Impale to not hit the other tank. If he gets it right back straight after, doesn't matter.
However, I personally don't find myself rage starved on this fight. Haven't seen any issue with my own TPS.