The goal is to get the fight to the ground but suppose you can’t take them down? He scoots his hips away from your clinch. That’s the time to use an old judo fighters’ trick and drag them to the ground and pull guard. Even though you are on the bottom you are safer than you would be standing trading punches with your opponent (given that you know your punch block series!).
Drill: Cup his shoulders (grab jacket, clothes, or ponytail), step forward with both feet, quick heavy pull on his shoulders as you squat down wide horse stance outside his feet) and shoot back. (Butt hits first, legs straighten before butt hits the ground, scoot hips back so you don’t pull him on top of you), Sit to punch block series stage 1.