With a lady I knew very well.  We were teasing each other with stories and ideas and she suddenly decided that she wanted to try two guys.  She had never done a MFM.  After a few weeks of thinking and imagining she set it up.  She knew the other guy.  He was another of her favorites.  I knew him through her and she made the arrangements.  We met in a local restaurant for lunch and got to know each other.  We were both very fond of the lady and trusted her as a match maker.  It turned out we were right.

The session itself was a wonderful exploration.  Neither he or I were bi so most of the action was us doing her in many different ways but we were also not afraid of a little mutual contact.  It is hard to lick a lady's pussy with a cock inside without licking a bit of cock too.  Ultimately, not my thing but it was a turn-on to try once.

My preference remains a long slow one-on-one session where I can really focus on my partner but variety is the spice of life!