Area and coordinates: 18,11 Dravania
Steps:
1. Jump into the hole (http://i.imgur.com/YemlPHR.jpg)
2. Try to get out
I fell into this hole at 18,11 in Dravania and the only way out is to backpedal into a specific direction (north-ish) while spamming jump. I thought I was stuck for good for a while. Obviously you can TP out or fly if you have it unlocked but that's hardly ideal.
Be careful!