When i was about 22 and lived at my parents home i watched the neighbours girl, which was one year younger than me. I knew her very good for years. Her room was very good to see from our attic.
I spent many hours there, but the only hot thing i saw till then was her in her bra.
One day i noticed that the light in her room was on and her blinds where open. I didn't expect to see much, but just took a quick look from one of our windows. I didn't believe my eyes when i saw her backside without bra. I immediately went upstairs to our attic to have a better view. From there i could see onto her bed. When i was upstairs at our attic window i couldn't believe my eyes again. She was totally naked, sitting on her boyfriend and having sex on her bed.
It was great. I instantly began to wank to that view

After they finished she stood up and walked through her room, totally naked. I could watch her in all her glory.
Since now, when i see her on the street or talk with her, i always remember how she looks having sex

And she doesn't know i have seen her.