because I was watching a high elo stream, and during his laning phase he used his Q to stun, then tibbers?

Personally, I tibbers and then stun - so the opponent gets 1-2 more ticks of tibbers before they can escape.

It really doesn't matter if it's single target.

Q is not a skill shot, and doesnt require you to get too close. Guarantees a stun, setting you up for your Tibbers burst.

In a 1v1 situation, yes.

In team fights, you drop Tibbers for AOE stun.

In team fights it's better to start with Tibbers (provided your stun is up) because it stuns them all in place

Laning phase when there's only 1 champion, you would usually use Q to get the stun off provided that you're in range. The reason that you would bust out tibbers first is so that 1) tibbers deals AOE immolation damage to the enemy and 2) longer effective range

I think single target you should use q first, so u dont mess up Tibbers.

In a teamfight just use the stun with tibbers to get most of the enemy team with it.

I open with Q.

Completely eliminates any chance of them dodging out of it, also gets the Q CD going a little faster so I can use it again another half second quicker. And really, if you're playing to win, there are going to be times that half second is really important and causes you to walk out of range of a jungler gank with a kill.

depend on if you want to AOE stun or single target stun

R>Q>W combo give high AOE stunburst
Q>R>W>Q give higher single target burst

If they flash and you tibbers... You waste your entire ulti... If you use your Q to stun, then it will follow the champ and stun them to where they flashed.