Trueshot Aura

Disengage – The ability for a hunter to make a large leap backwards while in combat.
A huge movement, with one keypress, in a known direction, that is NOT on the Global Cooldown.
Think about it. This provides the ability for bursts of movement at very high speed.
If there is one thing that causes a problem in PvE content for people, It is the inability for raiders to move at a reasonable speed out of Fire, or Acid, or Mana Puddles, or Poison Novas, Or even to be Not-In-Front-of-The-Boss when he casts X-Random-Flame-Breath / Frost Breath / Cleave

I have been known to use this ability a half dozen times in a single fight. While writing this I decided to check my guilds logs on World of Raids.
I could not find a raid where I used it less than two dozen times in a night. I also could not find a raid where another hunter in the raid used it more than four times.
There was one exception to that: Faction Champions – The hunter we faced off against liked to use disengage too.

Surely this ability should be on the toolbar of every hunter? Mages can’t resist using blink every time they have a situation where it is appropriate, Or just any situation where it won’t kill them. So why do hunters avoid this ability?
We can answer that question very easily. It takes time, and inspiration, to learn.

If you play PvP you don’t have the choice, You NEED to learn it, and use everything you can to win.
If you play PvE you have a choice, You don’t need to use every ability you have, You only need to do enough to stay alive, and to do the most damage you can. You don’t need to learn every little trick, And usually won’t even think of a lot. But despite not needing them to pass content. They can provide a significant performance boost. Tricks like this can minimise the time you spend moving. And minimise the amount of damage you take, giving your healers more time to focus on targets who can’t avoid taking damage.

Why use disengage in PvE ?
Disengage moves you roughly 15 yards directly backwards, with a roughly quarter second “cast” time (not GCD linked), then a quarter second in midair, and you have moved 15 yards in half a second.
Disengage will NOT be affected by slowing affects.
Frost on the floor on Anub’Arak in ToTC ? No effect on disengage.
Slowing poison from an add hitting you ? No effect on disengage.

Do you need to move away from someone or something ?
Face them, Tap disengage, Tap your instant-casts, Land in a safe position, Or closer to a safe position, wasting no time pressing E or Q (Or whichever key you use to strafe)
Death Rune centered on you on Iron Council ? Disengage Right to the edge, two steps and you’re out.

Need to move towards someone or something ?
Face away, Tap disengage. BAM, You’re standing in the blue rune on iron council, Or in range of your next target.

Even better? If you learn to use disengage, You will always be prepared to use it. You will face your back to the direction you need to jump.
Ever done Twin Valkyr ? You get annoyed losing damage with the wrong “buff” for your mob when you change?
Go sideways between groups, Stand next to the other colour swirlymabob. with your back to the one you have active.
DBM says “Change Colour” Right click on it twice, Tap disengage, Turn around before you land, and if the tanks are in a good position, you’re in range to dps the other boss until you need to change colour again, You are always on the best target for you, AND you lose less than a second of dps time while you move.

Now, A few extra things to note. If you have a parachute cloak, or slowfall, or levitate. You move even further while those abilities are active.
You can disengage in water, as long as you are in combat, by pressing Disengage, and Jump together while near the surface
If you jump before you hit disengage, You will get an extra couple of yards.

If you didn’t learn to kite in Classic WoW, LEARN TO SPIN IN MIDAIR
Combine that ability with a well aimed disengage, And you are the closest to an acrobat that you can be in this game.

If you do Icehowl, Face the wall when he casts his stun, Tap disengage when it reaches the end. You keep moving, in a “sum of two vectors” direction, and land away from the wall, in a nice position to run.

I could go into a huge list of encounters where you can use this fight to avoid random effects such as fire, acid, or poison, or where you need to move fast. Or even where you get slowed down regularly and might need movement. But I shall leave that up to you.