I have no idea what is going on and same with my guild. i take alot less damage then the other tank we have form the logs i took 9million less melee damage. the shock barely hits me so that isnt the problem. its the back to back 150k+ hits when he has the 100% damage buff is what hurting me. Here is the log. we did eventually get him down after we switch tanks.
What 100% damage buff? At 20% health both of them gain Furious which increase their melee haste by 30% and their damage 20%. your freally bad at keeping your Debuffs up, both his melee and the stomp are physical, keeping Scarlet Fever up is a 10% physical damage reduction. You're also eating the resonating crystal damage, as a tank you generally shouldn't be taking that damage.
Make sure your keeping those diseases up 100% of the time though. Having both Scarlet and Frost Fevers up will reduce those 150k hits to 35k and rather than coming every 2.4seconds rather than 2 seconds. Its about a 28% damage reduction from melee to have both up.
Always deathstrike just after a stomp not right before it. You don't need it to survive stomps and it gives you a nice big bloodshield for those melee hits.
Not keeping up diseases is asking for trouble first it will make the stomp do 11% more damage to half the raid which may give your healers trouble keeping everyone up and yourself will take more damage then needed, 90% damage *100% debuff=180% 100%*100%debuff=200% without scarlet fever you take additional 20% of a melee hit that just hurts. Looks like you're applying outbreak and then forgetting about it.