When one is describing fetishes, it's always helpful to have brief descriptors. i.e. "choking," "fisting," "spanking," etc. Specific verb actions that you can be into, and that others can read about and instantly know just about what you are talking about.
There is no brief fetish description one can use for the look a man gives you when he is beyond speech. When whatever you are doing for him or to him is making him so happy/aroused that he can't do anything anymore but just look at you, speechless and completely beyond rational thought. It's second only to the small little noise men make when you realize a specific desire or fantasy of theirs.
I'm okay without having a clean, single verb to describe these things. It makes it all the more erotic whenever it happens to not have a word to clearly explain it.