When you see the tail animation is when you use Lustrate. Eye for an eye is big and try to set up and manage the rotation yourself. Make sure your white mage is using stoneskin to the best if their ability and that your tank has a CD up or inner beast if a warrior. Make sure galvanize is up on the tank no matter what.

Every 2nd plummet expect DS to come after a fireball or conflag. Don't panic and you should be fine. Don't forget to use Eos during Phase 1-2, 4-5. Try to set up macro so your pet uses embrace when you heal to get the best results when infirmity is up.

If you or the other healer gets conflagged use your pet to heal tank or group and pet CD resist ability to recover easier.

Also comes down to your tank standing in conflag to avoid DS.

Good luck.