Beth and I were making love with another married couple, who were good friends and long-time swap lovers. I was making love to the wife and Beth and the husband were next to us thrusting away. I heard Beth starting to moan and knew she was going to come in a minute or two. She reached out, took my hand and put it on her breast and I started to pinch her nipple, which she likes. She started breathing harder and harder and I knew she was almost there. Suddenly she reached up and pulled my lips to hers, started fucking my mouth with her tongue at the same pace her lover was fucking her, and when she was about to come, she screamed her orgasm into my mouth as loud as she could. I cannot remember ever being more excited and I exploded in the other man's wife.