The back attack is probably the most premier, awesome spot. Even if you are on bottom, you are still in a superior position. The first thing Chris does is flop over towards his own knees to one side (preferentially the over hook side of the harness) to block chokes and clear hooks. A couple different variations of escape are demonstrated here. He also demonstrates escape when forced to lay on the under hook side of the harness. Sam Kressin demonstrates the escape when both arms are under hooking. Enjoy!