I think Shadow is exactly correct, although I have much less experience. First, I've read of similar feelings and descriptions by subs. Notice, not terribly different from "runner's high." Or, mystics. On that, I can speak. Many types in many places over the decades. Well described, even if the reasons are different.
My ex-gf, ex-sub, mentioned above, articulated similar. One time she called me and I immediately suspected she was drunk or high. Swore not, she had been thinking about some of her painful sub experiences. She was in a very happy place. Just by thinking, and remembering? Maybe not most women, but Celeste could come by willing it out on a dance floor. Or, just grab her bare ass and she'd start bucking and heaving and howling.
Never say anything like her before or since. And I have a well above average data bank.