Lord Jaraxxus is a fight with relatively simple mechanics, but a lot of damage. Jaraxxus himself should be tanked in the center of the room, and dps should spread out as if for Kel'Thuzad. This is to avoid the chain lightning as much as possible, as this will hit for as much as 15k and arc to 3 people on 10 man regular. Jaraxxus will also periodically cast fireball on the tank, which will hit for 15k, and tick for 6k every second for the next 5 seconds, so this should be dispelled as quickly as possible.

Jaraxxus will periodically spawn portals and volcanoes. Portals will spawn a Mistress of Pain, which must be tanked and burned down as fast as possible, as she will choose a random raid member, apply a Spinning Pain Spike debuff, pick them up and do 10 to 15k physical damage. Volcanoes will spawn 3-4 infernals, which should be tanked away from Jaraxxus. The infernals have an interruptable AoE which will hit everyone in about a 5 yard radius for 5k. The infernals will also sometimes turn into a floating orb, hover over to a random raid member, and exploding dealing aoe damage in a small radius. Tanks need to pick the infernal up again quickly, or it will start killing raid-members.

Jaraxxus also has a number of debuffs. The most important is Incinerate Flesh, which will be put on a random raid member (possibly an offtank) and which will absorb all healing on that target, till a certain amount of healing has been done, 70k on 10 man regular. This is not too much of a problem, as long as healers react quickly. If the debuff wears off without being healed through, the target will explode, dealing damage in a very large aoe, much like Vezax's flames.

The next debuff is Legion Flames, which will continuously spawn flames under it's target. There are two strategies for dealing with this, either the target can use damage reduction cooldowns and remain stationary, or they can run directly outwards. The idea with not moving is to not spawn as many flames all over the room.

A fire resist aura should be used at all times during Juraxxus, and any amount of passive healing or damage reduction that dps can provide will make the fight go much smoother.