There we were in the afterglow of the four of us having just completed the first round of group grope sex with each other. We, the two ladies laying side by side were enjoying a face-to-face embrace and nuzzling as our opposite hubbies were spooning us, when I felt a warmness that was way beyond sexual fluids of ejaculation and oral sex. It was pooling between the other wife and my crotches and, had grown to spread both upwards and downwards. Then I felt the fluid continue to spread back to my rear between me and her hubby.
Pulling back, I exclaimed "who is pissing in the bed?" We ladies quickly yelled at the men and both men claimed it wasn't them. The other wife also exhorted it wasn't her and I sure as hell knew it wasn't me! She said, "If I were going to pee on you, it would be in the shower not a bed that can get soaked."
Turned out, one of our friends that had been over earlier in the day and had used our bedroom to change her infant's diaper. She didn't even think...yup...it was 1972 and she had stabbed diaper pins right into our waterbed mattress. Guess the exertion of four full grown and highly charged sexual acrobats loosened the pin holes really well.
We realized what happened and our military husbands were quick to grab the duct tape for repairs, towels and fresh sheets. After all the night was young...and so were we.
By the way, she was telling the truth about the shower. We two ladies literally got into a pissing contest to see which of us could pull up our pussy and pee a stream like a guy. We never laughed so hard. (Ah the virtues of Jack Daniels)