Anything You Can Do, I Can Do Better...

Note to any level 100s coming back to get old achieves: you need to have someone with a tank SPEC in the group to do this achieve. Having a druid in bear form is not good enough if they aren't in guardian spec. No non-tanks can click the crystal.

This is mentioned in replies to main comments but I feel like it's not at all clear from the comments here.

To be clear: NOBODY can solo this. To do this you need a tank that can pick up the crystals, and the tank needs another person to hit with the reflect spell. So, you need at least 2 people, and one of them must be a tank spec.

As the ghostly Mogu Feng the Accursed runs to the first Mogu statue, two crystals appear. The one to the right (facing him from the entrance) is the [object=211626] which offers [spell=115856] and on the left (also from the entrance perspective again) is called [object=211628].

How [object=211628] works is it gives you an extra button like Ultraxion's twilight breaker or Madness' Dream which channels a link onto a target of your choice (you cannot target yourself) Pets are able to be targeted. Once your channeled target has taken damage from something (it can be anything in the fight) the copy button will turn into the ability that person got hit by but in a reversal version.

Here's a list of his abilities and their reversal:

[spell=131788] gives you the buff [spell=132297] which allows you to cast [spell=132293] (does not stack)
[spell=116157] gives you the buff [spell=118302] which allows you to cast [spell=115730] (can stop Epicenter by stunning during the cast and/or channel
[spell=116040] gives you the buff [spell=118300] which allows you to cast [spell=116936] (does more damage the closer you are to him, just like his kind. I recommend targeting pets for this one.)

[spell=116942] gives you the buff [spell=118308] which allows you to cast [spell=118197] (does not stack)
[spell=116784] gives you the buff [spell=118307] which allows you to cast [spell=116922] (just increases auto-attack damage)

[spell=131790] gives you the buff [spell=132298] which allows you to cast [spell=132294] (does not stack)
[spell=116364] gives you the buff [spell=118305] which allows you to cast [spell=116938] (does more damage the further you are from him)
[spell=116417] gives you the buff [spell=118304] which allows you to cast [spell=118194] (Decent damage... I wanted this one to have brackets too)

I have never been able to reverse [spell=118530] so either it cannot be copied or I am just unlucky. It wouldn't be good to copy anyway.

As for the achievement itself, you only need to reverse [spell=116040], [spell=116157], [spell=116784], [spell=116364], [spell=116417].
I didn't get credit for the achievement until after he died and got no notification for progress until the kill itself.

All that said, good luck!

EDIT:

Oh, and I finally found out the macro.

/click ExtraActionButton1

This allows you to macro the shroud of reversal to do things like this:

/target <Other Tank's Name Goes Here>
/click ExtraActionButton1
/targetlasttarget

This uses shroud on whatever person you name in the first part without changing targets. I'd imagine the click part also works for nullify if you want to use that it for this too.