The Trick
You would want to pick up the quest "Hard to Swallow". This allows you to throw dynamite into the mouth of the worms.
Step-by-step guide
* Grab the quest and head over to the elite Hulking Jormungar spawns.
* Nuke the mob down to ~75% and throw the dynamite when the mob beings to falter.
* Wait for it to explode and skin it.
* Rinse and repeat.
Farming them is very easy and there is more than enough mobs to go by.
Labels: farming, leatherworking