Anyone to help with Mouth of Zhaitan?

Theoretically I know what to do. Run around, dodge, kite, throw rocks when he opens his mouth. Practically? I'm not doing so great.

I've tried it like 20 times now, I'm just not exactly great at soloing champs.

I think I might have to unlock the lodestone closest to the story and go do other stuff until anyone offers to help. No amount of 'try and try again' is going to work when it comes to soloing champs, so will probably go and do more world completion in the mean time.

Found help.

Careful in HoT and PoF if you need help with this guy :)

I'll do my best lol

Pickup and throw the flaming boulders into the monster’s mouth while it is sucking up stuff.

You already know about throwing the boulders, so the only thing I can tell you is - you probably just need a lot of practice with moving, timing your dodges, and camera management. Camera management is something that some lower-skilled players just have a rough time with and the only way to get over it is lots of practice.

Until then, I'd suggest joining a friendly active casual guild and begging for help from your guildmates in downing the instances. That's what I did for the fight with Mordremoth in HoT on my Elementalist (which is a lot harder than the Mouth of Zhaitan).