The fight:
As you may know, Proffessor Putricide is a 3 phase fight, the last phase involves switching tanks to avoid a stacking debuff on the tank that does AOE damage to the entire raid, and if the tank dies with the debuff it heals Putricide.
The exploit:
In order to lower the raid damage, after the first tank switch have a paladin cast Divine Intervention on the tank with the debuffs, this will remove all the debuffs and as the tank does not die it does not heal the boss.
Your first tank can then taunt the boss back after around 2 stacks on the second tank, and hold it untill the boss dies, overall this gives you around 20 seconds extra time to kill the boss.
Obviously this is only limited by how many Paladins and tanks you have in the raid to how many times you can clear the AOE damage
Screenshot:
Cant exactly show you this in action, but a screenshot of the achievment...
Enjoy!