did you ever walk in on your parents?

I was the only one of 5 home one day, so I guess my mom and her husband thought they could get busy. I was 12? And usually always in my room being weird and antisocial. I needed something dumb like tweezers or something along those lines and I walked to their room and..... to this day as an adult with my own sex life I don't really understand what in the mother fuck was happening there. They weren't having sex but he was holding her up off the floor by her nipples. That was such a weird sight.   They both paused and looked at me like 😦 and he DROPPED her and she fell backwards on her Fucking HEAD.  
I RAN the fuck away.  I don't know what I thought but I knew for damn sure I didn't want any part of seeing that shit. 
I killed the mood I guess, according to my mother I looked MORTIFIED and, I definitely was. She apologized to me. And I still don't even ask her what in the shit was happening there because..what. My mom must be into some freaky shit. I don't know, on god I don't want to know and I'll be okay the rest of my life NOT knowing. 
Have you ever walked in on your parents?