Catching my Sister

Early last month I caught my sister Robyn 23 masturbating and using a rubber dildo, This was a surprise to me as Robyn has always been the miss goody two shoes type of person. Never did anything that wasn't prim and proper, I on the other hand have always been the black sheep of our family. I'm David 27 carpenter single and was again living at home with my Karen 44 divorced and Robyn. I had return home due to my last contract being completed and needing a place to stay till I got another one. With the coronavirus stopping most jobs, I contented myself repairing Karen's home and doing her gardening for her. Robyn was now unemployed due to the virus and Karen as a nurse was working a lot more hours than before the virus. I ordered in materials for the work I was doing and once it was delivered, I started work. Robyn was usually inside reading or cooking. Then I got some dust in my eye and went inside to wash my face and eyes in the bathroom. After I had finished doing that as I was returning outside I heard a soft moaning coming from Robyn's room and I went to see what it was. The door was ajar and I saw Robyn totally naked on her bed playing herself and a reddish dildo in her pussy. I was a little shocked but also got aroused myself and started to feel my cock go hard. I lent against her door and it opened up and Robyn saw that I was watching her. Then her eyes saw the bulge in my pants and she asked to see my cock. I decided why not and dropped my pants, she asked me did I want to fuck her and I answered if you want I will. She nodded and I undressed completely and joined her on her bed and we fucked. Since then after Karen goes to work, Robyn comes looking for me and wanting sex. I found out that that my sister is insatiable and will fuck with me anytime I want.