(This assumes your left hand is over body, right hand is down near opponents hip. You are laying on right side of opponent.)
Opponent is laying down on his back, you are cross body on top (Knees at shoulder and hip, right hand on ground near hip, left hand over body near opposite shoulder, weight centered low and back). Taking your hand near opponents shoulder, sweep back under neck and back up (Capturing neck inside your circled arm). Take opposite hand (one near hip), and feed through your body and grip your hand/wrist around neck. Move over opponents body, brace forehead on the ground near their left shoulder. At the same time, begin pulling your gripped hands to the right (neck crank), and then step your right foot over opponents body and finish the neck crank.