Cooldowns, How do they work?

Today you get an added bonus post. We have a tank in our guild who doesn't use his tanking cooldowns. As a healer you know how annoying this is. He's a Deathknight. I KNOW I KNOW I'm not hating on Deathknights but its very typical right? Anyways, Yesterday we're doing HM Sindra and our MT died in Phase 3 twice in a row and we were running by a few ways to save the wipe if it happened again the following conversation took place on vent.

Raid Leader: "DK can't you just taunt and Pop your CD's on Frost Breath while we Battle Res the Pally"
 
Pally Tank:"Yeah that sounds like a good idea"

DPS Guy: "You're asking him to use his Cooldowns?"

DK: "I don't use CD's on Frost Breath" 


Healers in the healing channel: "WHAT?!"

Anyway we killed it on next attempt without the MT dying in P3. This is just a public service announcement for tanks out there. Call out your tanking Cool Downs over vent or use the add on that says when you've used your CD's in raid chat. This will save your ass in sticky situations and help the healers know when to rotate their healing CD's. You'll make things a lot smoother. /Signed Healers Everywhere.

Y U NO USE THEM?