A very true story.
A couple weeks ago my wife and I and my sister, Dena and her husband and kids went to the beach. We rented a house and all stayed together. We were out on the beach and my sister was wearing a white bikini and looked really hot(She's 37 and has an above average body). I had never looked at her this way before, but today I got an enormous boner admiring her. I had my digital camera and took some pictures of her discreetly while she was sunning or splashing in the water. I was so horny, I knew I had to whack off. I excused myself and went back to the beach house. I downloaded the photos of her on my laptop, pulled my trunks down around my ankles and began beating off. It felt so good fantasizing about fucking my sister while jacking my cock. I knew it was wrong, but it didn't feel that way. I kept jerking my dick until I shot a load of cum on my chest and belly. Just then I heard, 'Oh my'. Dena was standing just off to my side and had seen me cum and the pictures of her on the computer. I tried to cover myself up, but it was too late then. Dena came next to me and said, 'I don't mind, I'm glad my pics could get you off'. She told me we can't do it here, but next time I want to take some photos of her let her know and she'll pose for me. Well, my wife's going out tonight and Dena is coming over. I can hardly wait.