When your opponent has your leg between their legs and is trying to get the underhook, frame on shoulder and biceps. Shrimp out, put your foot on the hip, and keep your knee outside their arm. Hold and pull your opponents elbow while pushing on the hip with your foot. Grab your opponents other wrist and place your other foot on their hip. When your opponent tries to break the grip of their wrist, let it go. Release your leg and bring it around their head. If you lack flexibility, push their wrist into their chest as they move forward and bring your leg around your opponents head. Immediately grab your shin. Lock up the triangle, raise your hips, cross their arm, and finish the triangle choke.