A lot of the time, I think the eroticism is born of the minor power imbalances. The ways our relative positions grant me power over you, and things I can do to heighten that disparity. And that's a lot of where I think the various eroticisms of discomfort that I like to talk about come from.
The degree to which your own discomfort indicates a desire, and yet it's a desire that I control your access to. I can choose to "correct my behavior" to mitigate your discomfort. Or I can not, and your inability to call me out on that is where I find the most eroticism. Sitting there, staring at me, yet unable to speak.
Why can't you call me out? Past trauma and patterns of behavior leaving a mark on you, a sense of politesse that compels you to act a certain way, or do we simply have that kind of relationship where I am above and you are below. In this precise moment, you are beneath me. Less about my own pleasure and more about just that fractional power. It's hot.