Fall more than 100m and live(single player only)
there are lots of different ways to do this but I have two good ones
Method 1. there is a big circular hole of water, coordinates approximately X:495.6, Y:792.3
Follow the trail to the top and jump off the highest point and you will fall very far and it should unlock.
Method 2.When you get to the story quest "lin cong I presume" you have to climb down a mountain with a little lake in it. Instead of climbing down walk around the mountain searching for the highest place. Should be the opposite site of where you start the quest. press down LS and jump. It should unlock.