Having a threesome with my best friend

The most unforgettable experience is having a threesome dating with my best friend and her boyfriend. We have been best friends for over ten years. Our relationship is purely friendship until last weekend. She and her boyfriend invited me for a movie with them. The movie was about threesome. After the movie, the atmosphere got awkward. Her boyfriend started to kiss me with her watching by the side. Then she undressed me and kiss my body. It was great I gotta admit.