k84guy here. I first became aware of my nature when I was around 20 years old. I had an absolutely fantastic girlfriend at the time. She was far from submissive in ordinary life but when kissing or making out she was very submissive. I didn't realize it at the time until one date night. She'd had a really bad day due to an absolute horrible college instructor. She'd been complaining about him for hours. That was very atypical for her but something about that day just had her frustrated. She'd been going on and on for hours when I decided I'd had enough. I grabbed her and threw her over my knee and started spanking her. She was crying in seconds. When I stopped spanking her she was in my arms apologizing for her behaviour and begging my forgiveness. She'd have given me anything right then. As we talked about what had happened I think we both became aware of a difference in the way we reacted towards each other. It was years later before I realized that we had a D/s relationship we just didn't know it.