My first experience was a sort of flash, but I always remember it getting me into CFNM stuff.
I was about 16. My friend and I were smoking weed in his backyard after school.
His sister who was a year younger than us was sort of hanging around by the pool, but wasn't smoking
with us; she was sort of a goodie good kid. A little chubby, decently attractive, brunette, glasses, and already had pretty big tits.
After a few minutes of smoking, I really had to take a piss. I remember my buddy telling me not to go inside to piss, since
I would stink up the house with weed smell on me (his parents came home in a couple hours). At the time, I had a decent semi going, and decided I was just gonna
walk over a few steps pass the pool and piss on the fence, having his sister "accidently" see my semi-erect cock. I wanted it to look like I was trying to get out of the way, and not be obvious about it, but angle myself just enough towards her so that she could see the whole thing. I walked over to the fence, checked out of the side of my eye, and saw that his sister got even closer to me. I don't know if she was trying to be sneaky, and get a peek at me while I was pissing (she knew that's what I was about to do), but that's what I felt like at the time. She was already kind of in to me, so that's what I assumed. She was at the edge of the pool, only about 20 feet away from me now. I was super nervous at this point, and the thought of her seeing my cock turned me so much that I all of a sudden got a full boner. I thought she may think it was a little weird I was fully hard at the time, but I said fuck it, and whipped it out anyway. My hard cock was curved like a banana, standing straight-up, and a little over 7 inches. I could feel her from the side looking straight at it. My heart was racing super fast; I took my hand off of it and stuck my hips out, trying to look even bigger, then I started pissing as loud as I could against the fence. It was pretty quiet in the backyard, so both my friend and his sister had to just sit there and listen to my loud ass piss stream hitting the fence. Once I finished pissing, I made sure to really shake my cock longer than usual, bouncing it up and down; Cause I could still feel her eyes fixated on it. Then I just waist-banded my boner, ran over, and hopped in the pool until my boner went back down, lol.
I would often times give her rides to and from school after that, since I just got my license, but I never heard a word from her about that day. We would still just talk about random shit, even though I know damn well she got a good view of my hard cock that day. I was just hoping I didn't make it too obvious