I guess it depends on your dynamic. You have to understand how it is to be a Dominant, in the same way you would see being a submissive. The act of just being “who you are” – while not being judged for it – is a reward in itself.
To me, the reward of having somebody who is willing to be vulnerable with me, emotionally-speaking, is the biggest reward. Who wants to serve me. Who wants to take care of me, but will allow me to care for her as well.
So, I suggest that you let him lead you more. Submit to him, emotionally. Open up, all sides – the most private sides you hide from everybody, even yourself. The tears. The laughs. The insecurities. The hardest parts.
If you are just talking sexually, I think the hottest things for me personally are to know what my submissive wants. What are her “fantasies”? What are the things she “wants”. What has she been thinking about today? Did she get wet when she heard my voice? Then have her tell me about it. Have her write it out, and how it made her feel. Have her masturbate, and record it, and send the audio to me. That shit is hot.
Plus – knowing those fantasies are essential – because as a Dom, you can use them later.