EDIT: Just noticed that it's UNIQUE from any netherdrake that's purchasable. It has a darker head and darker feet. So it's a true bragging right,
Requirements:
- Neutral or greater reputation with Netherwing.
- Epic Mount (?)
- Travel to Netherwing Ledge on your flying mount and get the automatic Dragonmaw Disguise/Netherdrake.
- Fly from the middle of Netherwing Ledge ALL THE WAY south until you hit the invisible wall (by this time you should just have a drake, no costume).
- Follow the south wall as closely as you can. Stay on this wall until you're south of Eclipse Point in Shadowmoon.
- Fly up towards shadowmoon. You can now travel around Outland on your new Netherdrake! Impress your friends!
Have fun!