Stay close and let the arm or arms which hit him stick to his body so you can keep working and finish the job. If you are tense and strike from the arm you will have to relax and change direction. Instead work on simply walking and having the arm move with you relaxed as one whole.
You can have a partner hit your arms as you keep them tense a few times if you need extra persuasion. and it is good to let them move freely from the lever point closer to the body from the point of impact.
Keep breathing and relax your eyes.