I was recently at a nudist beach and there was a couple next to me and it was only the three of us at the beach. They didn’t have a problem engaging into mild sexual acts in front of me (the guy had a boner, the girl was touching his dick etc) but that doesn’t mean they would want me to join them. What would be a nice way to try to insert myself in this situation and ask them to join them? Has anyone had luck asking a couple to join them in bed?