Back Mount Triangle

You are on your opponent's back, with your back against the mat:

Go from a seatbelt grip to grabbing a kimura grip, as if you were going to armbar them. On the side where you are grabbing your opponents wrist, place your leg on their hip, as if you were going to make a body triangle. Bring the outside leg over your opponents other arm, making sure the crook of your leg is on their carotid artery. With the hand grabbing your own wrist, hold onto your ankle, pulling it into your opponent's arm pit. Use your hand to lock up the triangle, and use your outside leg to hook your opponent's body. Make sure it's tight, as you shouldn't have to make pressure.