You are upside and opponent lies on his face.
Push your left knee against opponent neck firmly, insert your left hand under his right arm and grip his left collar deeply.
Lift up his right elbow, otherwise he may escape rolling the body his left side.
Grasp opponent pants(or belt) with right hand, pull up his body with your left hand.
Roll your body toward right back direction like your sit on his head pinning his left arm with your right foot.
Hold opponent left arm and head with your legs.
In this case, put your right leg under opponent's head like a pillow and twist your hip upward, so that you can control his movement.
If you pull his left arm, seize it tightly and turn it down,you can pin his left arm.