As a sub, I often don't give proper feedback because I don't want to be perceived as topping from the bottom. But how would I know you want to see me moan, to hear me suck in my breath, and to see my erection? I'm reading about it for the very first time from your query above. I am not a mind reader. In fairness, despite your superb ability to read people, you are not a mind reader either. That's because no one is a mind reader. And what about the subs you thought had a magical time, but didn't? How would you know? They never come back. All of this is a failure of verbal and nonverbal communication. If you want the truth, then you have to ask. I do not underestimate how difficult this is to do.