Can't Eat Just One

Easy Solo at Level 120 Battle for Azeroth and Beyond...

1. Mythic Difficulty.

2. Attack boss, bring health down to 30~40%

3. Run back to the furthest point away, the entrance to the room, basically hug the forcefield.

4. Hang out and wait around until 6 stacks of Ravenous are on the boss, mobs will come out which will request to be eaten, raising the stacks.

5. Naraxas will pull you in for some om nom nom nom now and then, just run back to the entrance if she does that. Keep your health up.

6. Once there are six stacks on the boss, kill it.

7. ?

8. Profit. Achievement Completed.

TLDR;

1. Let boss eat both adds and tank until 6 stacks.

2. Kill boss.

There are some achievements that you don't realize exist until add mismanagement floors the rest of your team and a clutch moment forces you to pet tank the boss through those last few percentages of health.

This is one of those achievements.