When we sat down for the meal, the battle lines were drawn. Beth and Robin put themselves on opposite sides of the table. Mark was quicker than I and chose the seat next to Beth. For a moment there was an awkward silence, then I put my plate down next to Robin's.

As we started eating, Mark very obviously placed his hand on Beth's exposed thigh and began to stroke it gently. She caught her breath and stiffened at his brazen gesture. But rather than remove his hand, she rested her own upon it, all the while staring directly into my eyes to see whether I would respond to the challenge. I said nothing.

After we had finished dinner, Beth announced, "I feel like dancing." Mark put some rock music on the stereo. I was sitting next to Robin on the couch, and Beth came over to me, held out her hand, and said, "Come on, darling, dance with me."

But I was still steaming about the dinner scene. "I don't feel like it right now, thanks. Maybe Mark does." As they bounced around the floor together, I put my arm around Robin's shoulder, and held her close to me. She responded by cuddling up to my side.

Meanwhile Beth and Mark began a provocative bump and grind, Mark's hands roaming up and down her body, Beth responding by rubbing her ass in his crotch. His erection stood out clearly through his jeans. I whispered in Robin's ear, "Let's go out on the porch."