Public Sex At The Clothing Optional Swimming Hole

My ex GF and I went to a nude swimming hole in Vermont. It was actually a series of waterfalls. We climbed to one of the upper pools. I told her about how I had watched a couple having sex there once. I actually talked with them while they fucked. My GF knew how much I enjoyed that and decided that we should fuck there. We were standing in about a foot of water and she was leaning against a boulder. I was fucking her from behind. Another couple climbed up and saw us. She wanted to turn around but he wanted to stay. He was clearly enjoying the show. They were both nude and he was hard as a rock. She kept looking away and covering eyes but also peeking and giggling. She playfully tried to hide his erection with her hand. I puled out and came on my girlfriend's back. It was so cool to be watched by a couple. The cumshot was icing on the cake.