This is a side control drill to help maintain position. It’s called The Dragon Whip Drill. When your opponent gains access to an underhook, this is when you would execute the dragon whip. If your opponent starts to roll to his side, he’s either going to go to his knees or recover his guard. So, in order to prevent this and maintain side control, you’ll overhook his arm, post your left leg out so that it’s in line with his head. You’ll post your hand on his neck. Now, as your left leg drops to the back onto the mat, the back leg will back step and your left arm (elbow) will now drop in front of his body. Watch this video as Professor’s Guy and Rob demonstrate the dragon whip drill, and help you maintain your side control.