This is a true story that I have never told anyone before.
When I was 25 and my little sister was 18, i would jerk off every chance i got (as boys at a certain age do) and there were multiple occasions that my sister would walk in on me doing it. We shared a bedroom with bunkbeds for years which made privacy difficult, for both of us. At first, I thought it was disgusting and I'd get so nervous for getting caught doing it. I'd gotten better about locking the door or waiting until everyone was asleep.
Anyway, some years later our parents went for holidays and we both alone were at home for a week.
And a secret of mine would be i smoke joint sometimes and those days i had the best time and joints of my life and would feel so fucking horny all the time.
So the first night, i came home after smoking alot of joints and my sister was sleeping ( i thought ). the room was full dark with a light of bulb which was dim and after getting on my bed i felt horny and started watching some porns.