I remember it clearly, I think it must have always been dormant, when I was thirteen or fourteen I was channel surfing really late one night when I should have been asleep.
I was just starting to discover myself in a sexual way, and to experiment with how teens experiment. I came across a film called Starlet, a low budget porn film about making low budget porn films, in time for a scene where a woman is forcibly stripped and locked into a pillory to be whipped before the director called cut and everyone left the set leaving her locked in there.
The scene, and the fact that it excited me, shocked me and made me very shamefully turn the TV off, but for pretty much the whole week afterwards it was all I could think about. At the library the next weekend, I very self-consciously tried to explore for something along similar lines, both to understand why it affected me so much and to find something else that might excite me as much.
To this day, it remains my most powerful fantasy, yet I still haven't gotten around to trying it.
The damsel in peril thing that pervaded kids and adults TV inspired my early fantasies as I came to try and understand what this thing was, and going to bed with a new fantasy I'd thought of, seen or read about that day became a kind of fetishized ritual. Once we got the internet in the late 90's I was able to really start exploring and expanding my horizons. That's when I discovered self-bondage.
Even back then, I bursted to tell my friends the things I thought about, but never dared, which is probably for the best