Bite.
(Remember - Dogs don't know kung fu)
Don't open your mouth wide or try to take a big bite at once.
Nibble. Like eating sweetcorn. Take out tiny chunks in quick succession.
He will pull away.
If he is in distance, bite his neck, ear, nose.
If a man has closed to grappling range and got you in a choke he is a dangerous opponent. He has got passed your punches, kicks, traps, locks, HKE, chokes, and got you in a clinch and out manouevered you.
You MUST use 100% response and your most deadly response.
Bite.
You have been practicing this move 100 times a day for at least 3 sessions a day your whole life. It is your most practiced move. Pull it out when you need it - it won't let you down.