I had a threesome with my best girl friend from high school & a guy we both liked. It was lots of fun, but, as there was no PIV sex, just oral, I didn't really think it was that big a deal. Well, I later found out how other people can get very jealous & conflicted about threesomes and it's not something I would ever again enter into lightly.
As an adult, I would love to have a threesome with two men because I'm greedy! Really, it's been a fantasy of mine because I would like to have as much PIV sex as I want without having to take a break. I don't know that it would ever be realistic though, because I only want to do it to please me & I'm not as interested in their needs, (as far as my fantasy goes), plus, I don't have casual sex.