Sik Parry Bro

On the platform just before Sikran's room you'll see these four weapon racks. Before you pull make sure 4 players have clicked them.

Once you're on Sikran's platform you'll get an extra action button. There appeared to be several different ones based on which weapon you picked up, but they all function the same so I won't bother linking the different ones.

Once pulled, you need to walk up to the boss and use the extra action button while facing her. This will do some damage to you and give you the [spell=451759] debuff, increasing your damage taken by 20% for the rest of the fight. It will also knock the weapon out of your hands onto the floor and someone else can then click it to pick it up and repeat the process. Once everyone has the debuff you can kill the boss.

Anyone who dies will keep their debuff so it's OK if people die after using the weapon on the boss, but anyone who dies before they get their turn needs to be rezzed.

The weapons aren't that big when they drop to the ground and can be hard to see under the clutter of players and mechanics so especially with bigger group sizes I'd recommend moving the boss a bit so people can see them on the ground. If you have low geared people that you think might not live the fight you might want to have them go first.

If you have questions about the metas feel free to add me to Btag or Discord!
Btag - FrostyShot#1667
Discord - yarini

You can use every weapon on the way from bloodblound horror to sikran, so you have like 7 or 8 weapons for the achievement

As of this comment, Druids aren't able to obtain said weapons in Bear form, so you have to do it while your co-tank is tanking the boss.
I suspect it's the same in cat form, but i don't know.