I know this might be a bit odd but its true
I was 15-years-old when I first discovered masturbation and my first orgasm.
One night I was lying in bed and heard weird sounds from my parents room. I didn't really pay much attention but couldn't fall asleep. A few minutes later the sounds got a bit more intense and I began to feel really tingly in my vaginal area. I shared a room with my brother who was 17 at the time. I noticed he wasn't asleep yet either. I slowly slid my hand down into my sleeping shorts and felt my area a few times. I noticed the clit felt great and continuously rubbed it. I was a bit bothered because I knew my parents were having sex by now.
I looked over at my brothers bed across the room and he was lying naked furiously stroking his penis. I never felt attracted to him but I wanted to tease him. I kicked back my covers and exposed my self masturbating so he could see me. I heard groans as he cummed all over himself. He fell asleep and pretended nothing had happened.
Five minutes later I continued to rub myself, faster and faster but lightly. I heard my parents groan and moan and for some odd reason it turned me on and made me very wet. The sounds stopped so I did too since nothing was happening. They eventually picked up again and went on for about half an hour. I masturbated myself to my first orgasm and moaned enough so my parents would hear me.
My mother walked in my room to see what I was doing and told me I shouldn't let others know what I was doing. To my surprise (I know this is gross, now that I am 19 and think of it) she asked me to come into her bedroom. I did and she told me to lay down on the floor next to the bed, so I did. My father and mother started having sex again. I rubbed myself to the most intense orgasm of my life. We never spoke of this again but it was a great experience. After that I tried to keep myself quiet while doing it but me and my brother would end up watching each other once in a while since we shared a room for sometime.