You got better luck with your female friends than you do with your girl. Actually, if it's a small group of female friends, that's the best chance for a threesome. If you the super cool homeboy, u might be able to get on some lets play spades for shots shyt and one thing might lead to another. Can't be no real feelings involved, this shyt best works when casual and spontaneous.
You might be able to get your girl to do it, but feelings will be caught one way or the other, especially if you are the on setting it up trying to persuade her. It's an attention issue. Ho's don't be on that sharing shyt, no matter what they say. Don't ever let a bytch fool you into thinking they not the jealous type. And if you don't have a certified freak, then they won't wanna participate on the other girl, leaving the session awkward and having your girl feeling left out when you on the other bytch