If you do this strat, your tanks should -NEVER- have breaks during feuds aside from the ones that are applied during feud and never be in serious danger of being gibbed. Assume you have a Righteous Fury Ret Paladin / DPS DK in Blood presence named Joe, as well as Tank A named Andrew and Tank B named Bill. Also we are going to assume worst case scenario (Back to back feuds all the time)
Joe initiates the fight and get pounded on, and healers keep him above 10k. Double attack buff happens, and Andrew taunts for the double attack. Double attack happens, and Joe taunts it back. Massacre. Repeat the cycle. Massacre, feud starts. Andrew taunts and hold Chim for the entire feud, using a short cooldown (30 sec - 1 minute) + a longer cooldown (2 minute CDs will always be available due to the nature of this strat. 3 minute cooldowns need to be rotated) when the double attack buff pops up. Feud finishes, massacre happens. Joe is back to "tanking" single attacks while Andrew now has breaks. He'll just dps the best a tank can while Bill now taunts for the double attack. Joe takes it back, and massacre. Another feud. Bill taunts and tanks the entire feud, using the same CD strat as Andrew. Massacre. Joe now tanks single attacks while Andrew's breaks have now fallen off and taunts for double attacks. Massacre. Andrew taunts and tanks the entire feud, using the short cooldown plus his second long cooldown (or his 2 minute cooldown again; it'll be up by now), survives, massacre. Joe does his thing and Bill taunts for double attack. Massacre. Bill tanks entire feud doing the same cooldown method as Andrew. Massacre. Joe and Andrew do their thing, Massacre. Feud happens and Andrew tanks. The 3 minute cooldown he used on the first massacre is up by now and the entire process repeats from here.