Just watched....

So I'm hanging out with my best friend and her man and I'm minding my own business. Next thing you know I started hearing kissing and moaning. As I look up, I see him licking her dark round nipples. She started to grab his long black cock. One thing lead to another. I was watching them having full on sex in front of me. I felt so uncomfortable, but so turned on at the same time. Has anyone ever experienced this?