This happened when I was in high school. I was a pretty horny teenager. I had been watching porn for awhile, and jerked off more than anyone could imagine. One day durning class some people were talking about how some people could suck their own penis. I was mind blown thinking damn you gotta be huge for that either way I was very determined to do it. I get home from school, and go take a shower as I don’t like walking around in my own filth all day. Then I decide it’s time I’m gonna go try to suck my own dick. I head to my room, get on my back and kick my legs behind my shoulders trying to reach my dick with all my might. I really didn’t get close, but I keep trying. Then I hear my door barge open to my dad standing their staring at me I could have sworn I locked my door. My asshole is pretty much pointed directly at him possibly seeing my nuts swaying way. He quickly shuts the door and runs off. My dad and I have never once talked about that moment to this day. I just can’t imagine the trauma I probably put in his mind.

TL;DR attempted to suck my own dick when I was young, dad saw, most likely caused him PTSD