The Master Lock series is some crazy ish once you have your opponent's back. I actually saw a video from the guys at Team KYFA where they were playing around from the position before this and called it the 'Ghandi.' But this kid in the videos has really developed the position.
In the beginning of the video he gives credit to the Puppet Master series by Jeff Barney that you can find at No-Gi-Grappling.com on the Rubber Guard page.
So the setup for the position is when you have the back with wrist control on one of your opponent's arms while you are going for the RNC. What you do is trap the arm that you are controlling with your leg, shift your body so that you can bring your leg behind your opponent's back and then you lock it in with the arm that was going for the RNC.
I know, I know ... sounds crazy. Just watch the vids, there's no way I can explain this.
On a side note, I found it hilarious that the guy is working all this stuff in his living room.
