Threesome

Whenever I watch porn, I always cum from watching a threesome. it's like a fantasy to me. Well now I want to have one. But how? I'm so nervous but so curious. I don't even like girls and have never been with another girl but the idea of the whole threesome is a big turn on. I have the perfect male (just a friend) to have one with but just not sure of the girl and how to even get comfortable enough to go through with it 😩