Joined my BFF and her bf and loved it

So a few months ago my BFF came to me and asked if I would join her and her bf for a threesome as a surprise for his birthday.

I was hesitant about the idea but she eventually convinced me and we set a time and date.

We showed up to dinner dressed sexy and surprised him with the news. Once we got back to their place we started it off and what was meant to be a one time thing lasted for the whole weekend and now we have done it almost every weekend since.