Watch the video here on tankspot if you havent already. I can however give you some advice about it since I have OTs this a few times:
- Its all about ooze control and to be more specific to get everyone infected by mutated infection to get their ooze to merge as quicky as possible. In the first few attempts on this fight most ppl tend to run out to the edges of the room first and then try to find the OT/big ooze. Make sure all your dps/healers have a good idea of where you or the big ooze is at all times during the fight so that they immediately run to you when they get infected.
- Some ppl run towards the OT when they get infected even when there is a big ooze present. Since the big ooze is significantly slower than you are this can delay the merge. Tell everyone to run straight through the big ooze to get rid of their ooze. I dont think I have ever seen a merge fail when that is done but make sure everyone knows that the merge needs to happen before they can go back in.
- Marking the first small ooze with a skull is something I have found to be good since two ppl with small oozes trying to merge with eachother can make it take longer than needed. The first person with a small ooze should run out to you and then stand still. This is because the small oozes are as quick as we are so trying to outrun them doesnt work (unless you have a DK OT who chains them down then you can stay about 10 yards away). The melee hit from the small oozes is only about 100 per hit if I remember it correctly so avoiding that or not doesnt make a big difference (the damage comes from their aura something like 4k per tick.
- Make sure everyone knows to move after the big oozes have exploded and not before. As the OT you might want to be the one calling this out since you have it targeted.
- Dont be afraid of running through the flooded area if its in your way, it doesnt hurt that much and bringing the big ooze too close to the rest of the group does a whole lot more damage.
- Never get hit by the big oozes melee swings, they do a lot of damage (cant remember if its 20 or closer to 30k). If you ever find yourself in a spot where you might get hit by it pop a cd.
- If done correctly this fight is easy to 2 heal but its a pain if not.
- Attack the big ooze as often as possible with your ranged attacks to keep aggro and also if possible try to attack small oozes since they sometimes seem to have a random threat value from the people they spawn from. This will also help if that person dies so they dont always go straight for the healers (which they tend to do)
- Slime spray is something everyone should avoid but this doesnt really fall into your responsibilites.
Those are a few things I can think of.