Resto
Legend
I can't get both windows open at the same time. It's either the mog window is open or the character window is open, not both. FeelsBadManWear the armor type helm for your class, eg, if you're a rogue, equip your boa leather helm. Click on xmog npc, select helm, choose your xmog that you would like - this MUST be another cosmetic item. Next, open your character page and drag mist-piercing goggles onto your character to equip. You should now be able to activate the earlier selected xmog onto the mist-piercing goggles. Remember, the xmog must be another cosmetic item.
Good luck.