As you are in the mount and prepare to deliver strikes, your opponent attempts to reverse you by underhooking your leg.

You attempt an arm bar but your momentum aids in his escape attempt. He begins to roll with you and sit up.

You lose the arm bar in the shifting and end up in an loose open guard. Your opponent takes this as a complete escape and shifts to the attack.

Hold onto the arm tightly and pull it up past you!!! Bend your (L) leg down across his neck (leaving no space) making sure it is perpendicular to his spine. Hook under your other leg and tighten up. Squeeze your knees together (don't focus on straightening your legs) !