I sat back, my wife lay collapsed, semen dripping from her skin, and our friends lay down to recover.
When the heat of sexual excitement cools, the atmosphere equally cools; but, in a friendly way, our guests, no doubt due to their maturity, comforted each other lovingly. I stood and pulled a cover from the dresser, and offered them the couch. They took the cue perfectly and rose to leave. She came to me and kissed me full on the lips, rubbing my cock as she did so; he turned to my wife and bent over to kiss her on the cheek goodnight.
It was so relaxed, so mutually respectful. We haven't repeated the event up until now, but sure as hell we fucked a lot that weekend after our guests left the next morning.
If you're thinking of sharing with another couple, oral only and same room sex is definitely a comfortable way to start.