idk how this glitch came to be but its awesome, its one of the many mage slow fall glitches ive found, i was able to jump off of anything (in this case dalaran) hit slow fall and start LITERALLY swimming through the air, (other possible was i buffed slow fall, mounted jumped, then buffed again but i dont remember, of course when buffing slow fall, mounting, and jumping (be4 u hit the edge) it is also possible to see your mount "slide" through the air (no leg movement) or running off the side and see your mount "run" through the air
ive found its both easy AND fun to use these glitches and other interesting flying glitches, it is apparent tht WoWs air boundries and flight rules are not nearly as exact as (parts) the rest of the game