Some ppl is looking for this bug because it is really really nice. Follow these steps and it will work.
MAKE A MACRO WITH THIS COMMANDS:
/logout
/console logout
1. Go to a zeppelin or a boat. Die beside it, not on the boat. By making at war with orgrimmar, if you are at zeppelin tower outside org. So die beside zepp, wait until zeppelin arrives. And hit release spirit.
2. Run as ghost on the zeppelin/boat and press your macro. Then you will get DC.
3. Log in
4. And now you got the buff! Now you can solo instances, and much things.
To remove the bug: just die. Fall die, jump off the edge in outland.
NOTE: This bug doesnt work at all servers. DO NOT KILL PLAYERS WITH THIS BUG! They can see in combat log who killed you. And if nobody was there when he died. Then you can get caught. Be careful. If a GM appears you. Then just leave the place.
If this already is posted, then i am sorry. But i didn't find when i searched.
Enjoy
EDIT: If you dont want this to work on YOUR server, then delete all zeppelins and boats! Then they cant get this bug. You can make portals.