Share the Pain

First we Shared the Love and now we will Share the Pain.

The thing that people don't understand is due to the wording. It's not based on how many stacks you have, but how many times you have received the Torment debuff in any way. Basically, if you go to the crystal to receive torment more than three times, you won't receive the achievement. If you DON'T, regardless of how many stacks you took each time, you get it.

DPS race achievement. The better your dps is, the less crystals will spawn and the easier it'll become. With 370+ geared raid in 25man, this was relatively easy to do (accidentally, I might add). We used 6 healers, and looking at the logs we had 2 ranged group DPSers not taking even 1 tick, and we still got the achievement. I can imagine 10man being harder with just 5 dpsers, but it should still be doable.

My biggest advice would be to have good communication. We separated our ranged crystal group (10), melee crystal group (7) and healers/tanks to different vent channels. You don't really need to know who's healing who when you're organizing the rotations for crystal tanking. Use dispersion and other similar cooldowns to prolong stacking so that you only need 2 people for a crystal every now and then. Shadow priests might want to switch SWD glyph to dispersion glyph, you don't want to use SWD with the +250% shadow damage taken debuff.

EDIT: Like Silhac pointed out, this achievement is about how many times you have the debuff that you get when you leave the crystal. Not about how many stacks you get before moving out from the crystal.