Fastest way to level a pet?

I recently got my rainbow phoenix and I was wondering what would be the fastest way to level it? I dont care about evolution stages etc..

Death Levelling I would guess.

Wurms, in HM.

Shadow

Can't do that with the rainbow phoenix (death leveling)...At least that's what I heard. I'm a dervish by the way

Make sure you have the only pet, if you have more than one pet in the party, the pets share xp just like your party members do, the more pets you have in the group, the less xp they will get.
I Run a Healing build and take him into HM with scrolls.

Even though it counts as a normal pet there, for the Hall of Monuments. Not to mention the Rainbow Phoenix is a sure sign that you have rank 2 of KOABD and, as such, is a "prestige" pet. Nor can you death level it, you have to enter your HoM *alone* so no one to rez you after it kills you, nor is there anyone else for it to repeatedly kill. If you die you are zoned back into the EotN.

The fastest way to level 20 I know of is Wurm farming in HM - it doesn't take long at all for the pet to reach level 20 even in a full group and no scrolls. I leveled my regular Phoenix to 20 this way as when I capped it and I didn't want to bother with death leveling as I figured I would just level it while doing SS/LB runs (however, being caught by the bug that doesn't let me enter it into my HoM it ended up being a waste of time unless Anet decides to fix said bug, or I go death level one until I can get it in my HoM). This was also on my Dervish which is my main HoM character.

You will have to ask someone else how the EXP is divided and if scrolls work on pets - I do know their EXP gain is different and I'm too lazy to look through the wiki.

Just play with them normally, I don't see why there is a need to hurry up leveling your pet unless you're going for Dire or Hearty (do you even need to try?)

Just be glad you're not death leveling a Dire pet...zzz...

Aside from death leveling, which you can't do with the pet you've acquired, I've found that HM Wurms is best. I was LB/SS farming anyway, just like someone else mentioned.