Just to add to the discussion, very interesting reading. I am pretty new here (around 2 months). But already had two experiences of group sex. Opportunist I believe. Got invited, hesitated then jumped in (MMF). In the end I had a lot of fun, although not being very experienced in descriptive, I think every one had their fun.
Second time, I got ambushed while discussing with a woman and accepted her invitation to find myself in a room with her and a friend of her. I was a bit surprised but in the end after having a laugh and discusion agreeing, it was well worth it. Discussion and sharing