I'd say the BDSM examples in mainstream media as I was sexually awakening were more indirect than mild. It's hard to appreciate now, but Wonderwoman (with her golden noose, and getting tied to a chair every other episode) and Catwoman (tied by some villan to a machine that would slowly kill her), et al in their revealing costumes were as close to sexual situations as TV got at that time.You could say that Linda Carter was my first love, and she never even knew it;) Slasher films were all the rage, featuring young teens sexual explorations interrupted by some guy with a knife.
Sex as powerplay was a real theme in both mainstream media and real life. Universally, a woman held power and respect by not having sex (or witholding sex). Things reversed if she gave in.
For me, it wasn't so much a matter of discovering that my BDSM urges existed, it was a matter of integrating the power exchange and sensation play that everybody was doing anyway.
At the same time, sexuality wasn't discussed openly, except that deviation from the norm was truly considered mental illness: Doggie style was Kinky and BDSM was completely taboo.
I brought rope along the night I had sex the first time, just in case my girlfriend was "kinky". She wasn't kinky at all, and suggesting she might be risked her taking grave insult and breaking up with me, so the subject really never came up until my 20's. Once we started, it all flowed from there, and the exploration continues.