It was my Dad's birthday and his wife invited me and my sister's family to have dinner at their place. Since I've divorced two years ago I've been having an affair with my step-mother. She found out my Dad was screwing many of his college students so it wasn't difficult to make her open up her legs to me. This was already at the end of the night. My sister, her husband and kids were already left and my Dad was on his bedroom watching TV. Well, we could ear the TV but he was already sleeping probably. We went to the guest's bedroom inside the bathroom and I got to fuck her before I went home. I didn't know she had prepared the all thing, only after she send me the video a few days later I knew.