Wifes Stepsister Comes Over to Have Sex with Husband Next to His Wife

My naughty little stepsister came visiting us. She was supposed to sleep in the guest room. Anyways, I know this horny bitch, so I was not surprised when she entered the room and they started to make out next to me. This was actually exciting, just laying there, making them believe that I took a nap and listened to them while fucking... The hottest was, when I heard him creampieing her!