I don't like having sex with another guy around. To me, that is like taking a double date too long, and even mixing it up.
And having a foursome with three women, that is getting hectic. A threesome is a great concept, if the chemistry is there. But that is very important, I have seen too many scenes, where the babes move around and half-heartedly switch between both partners.
Then again, if both women are into each others, that is what Im talking about.