First... Do not initiate coversations with a coach
Second...respond to legitimate questions. Do not respond to statements unless to warn or whack a coach for unsporting comments.
If you answer a question and the coach wants to argue. Give him the "asked and answered" response and then let him have the last word. If he continues with it it might me warn and whack time.
All responses should be quick and to the point. If you get to verbose they will turn it on you and hang you with your words.
When in doubt, no response is probably the best response.
Understand the game and the coach. When you can show your human side and maybe inject a little humor to lighten him up you can do that. Again if you are not sure this will work do/ say nothing.
Use passive phrases like "you may have a point, I will look", "if it happened as you say, then I may have missed it" "ill take a look". Also, if you know you booted it tell him so (you only get a few of these a year!!!)
Use please and thanks when making requests of coaches.
If none of this works, he is an ahole and should be ejected