2 Part Technique - If the opponent escapes your Seat Belt Control by putting his shoulders to the mat, switch to the Over Under Pass vs Half Guard to stay in a good advantageous position. During your transition, he may instead swim under for a Deep Half Guard. It would be great to just use the Under Hook and Head Control and sprawl back, but he might be to close to establish that control. Immediately press down on the opponent's head and Sit Over, because he will sweep you or escape if you hesitate. Control the position by weighing down his arm with your body. This new situation should be very familiar to you, because the position is the same as the Back Step Pass vs Half Guard.