It started like any other fantasy.
I would be horny and bored, and would go through all of the various sexual permutations in my mind. My brain would put things together to see how they fit, what kind of response they elicited in me. When I stumbled upon one I liked, I would latch on, my breath would quicken, I’d push it to further and further mental extremes until I finished, usually with a slight pang of guilt over how far I’d pushed the fantasy, how extreme I’d made it.
This one started simple. Exhibitionism. The desire to be seen by others in a sexual scenario, and for them to be turned on but unable to partake. Only this was a sort of compersive exhibitionism as it wasn’t me I was most interested in showing off, but rather Her.