I didn't have very many bondage or D/s fantasies when I was younger. But reading over sections of this thread it's occued to me that when I was 13 or 14, I had a fantasy about a girl who was a classmate of mine. I wanted to take her out into the woods, we'd get naked, begin making love... and then I'd tie her to a tree, and go on making love to her and taking her body for my pleasure. Around that same age I also recall having several fantasies about being a sort of on-call love slave who's duty was to pleasure this insanely beautiful woman however she wanted me to, and that was probably the first FemDom fantasy I had, though I didn't know jack about kink at the time.
I'd certainly never heard of the term bongade, or BDSM, or D/s at that time and had no clue what I was onto, and I wouldn't really discover what those thigns were for years after. Most of my adolescent fantasies were more or less "vanilla" material.
I'd totally forgotten about that but reading over some of this here reminded me of it. That's the first tangeble sexaul bondage fantasy I can recall, and both my first "Dom" and "sub" fantasies that I can think of.