This leg-lock is applied as you escape your opponents guard.
Use the elbow drive method to apply pressure to your opponents thighs. This should cause them to uncross their feet.
Now step over your opponents left leg with your left knee as shown. Your left foot should be resting on their left hip and should stay there for the rest of the technique.
Hook round your opponents left leg with your right arm.
Twist on to your left side and grab your opponents leg with both hands as shown. Now arch back and push your hips forward.