Masturbating In Front Of My Wife’s Friend

We went on a family trip – my wife, our roughly one-year-old child, and me. A friend of my wife also joined the car trip. We rented a cabin along the road that had bunk beds. My wife and our child slept in the lower bunk, and her friend took the bunk above them. I lay down in the other lower bunk, directly beneath my wife’s friend, who could look straight down at me. I was very aroused, and when everyone had fallen asleep, I pulled the blanket down a bit and started masturbating. My wife’s friend lay watching me from the bunk above. She seemed very interested. We never talked about this afterwards.