A buddy showed me this about a week ago.
There are two very easy ways to complete "The Big Bone Worm" in The Bone Wastes in Terokkar Forest.
You simply hit one of the Decrepit Clefthoofs from around this point on the map:
And kite it to one of the tunnels into Auchindoun and kill it. Make sure it isn't actually on the entrance to the tunnel, slightly in front of it:
Once its there use the Thumper on it. You will get one of three: The actual worm you have to kill, two of the Bone Sifters or three Sand Gnomes...*shudder*. Repeat the last two steps until you get the huge worm. Its bugged so he just sits up top and stares at you, shooting a poison bolt every 15 seconds are so.
There are two options now: if you are ranged, you can simply kill him, bandaging once or twice.
However if you are melee dps, like my pally, you can just run around the corner and wait. He is on a timer, if you don't kill him in a certain amount of time he just dies and you can loot the worm parts. Easy right?
Loot the enormous worm parts, get your dagger and a bunch of xp for doing little to no work
Happy Hunting!