lktknow

Sex is nobodys business except the three people involved.
I used to have a t-shirt that said that on the front of it.

the whole threesome scene can , imo, be a deeply satisfying experience for all involved, or it can go terribly wrong, like someone else said.
It's sort of like, you don't really want to do it with someone you are going to see on a daily basis, or sit down to Christmas dinner with..but then again, you don't want a stranger, or someone you don't know at all. But where do you draw the line, its like you want your fun for the night and then you want them to just go away, or it to be over...but, if it's someone you don't know well, there is always the risk of them becoming a drama queen about the entire matter, and could turn out to be your worse nightmare...all sorts of scenerios come to mind, blackmail, stalking, etc.....any way you look at it, there is a lot of risk involved..but that is a part of the allure, I suppose.
I'm no expert, but I would venture a guess that over half of these types of things turn out to be not only NOT satisfying , but destructive to the relationship. Human emotions are so hard to be exact about, because no one really knows what they are going to feel at a given moment until they are experiencing it.
And just because the two of you feel you are mature enough to handle it, who's to say the third party is..unless you have the pep talks with them also, before it transpires...and then you have the aftershocks...like the earthquake, where the both of you have your minds to deal with the visuals of what you saw the one you love doing...and it hits you sometimes at the most inopportune moments.....and it can be a real mind blower.....
In my opinion, the fantasy should remain just that, don't act on it. The odds are not in your favor ..but then again...??
Experience is what you get when you didn't get what you wanted