I am about to have a threesome with my friend

I have heard many times of my friend talking about his threesome hookup with his girlfriend. There was woman and man. Thay had it a lot. I never would have thought he would invite me into his kinky game. He was serious about it when he brought it up to me yesterday. I was a little shocked but also curious. I told him that I would think about it. I think I am going to say yes and have a threesome dating with my friend and his girlfriend.