Trying to figure out the dynamics of being able to communicate between each other during different situations is very difficult. My little one and I have been together for years and still it is easy for miss-communication to happen. He doesn't like to talk; I don't let him get away with that.

You need to be able to express your true feelings to your dom, and a good dom will want to know your true feelings. He may still want to do things you don't like (sometimes that's the point), but at least then you know he has full knowledge of the effect that it has on you, and you can trust him when he "overrides" you that he knows what it's doing to you.

You need to talk to him about how he would like you to communicate your feelings to him. Talking about things not in the heat of the moment is best, but sometimes it can't be avoided; sometimes things sneak up on you. Unfortunately good communication is the kind of thing that only comes with practice and hard work on both sides.

But as long as he wants to know how you feel, you should be able to find a way to communicate that with him (and if he doesn't care how you feel then that's a problem). Maybe, instead of saying plain "no", he would be better if you phrased it as a question. "Would it be alright, Sir, if you did not do that right now?" That gives you the opportunity to say how you feel, while still leaving the power in his hands whether it happens. That is just one suggestion I have; you have to work out with him what is best for you both.