True Story. Not group sex per se but certainly nudity and sex in a general group.
I had been trying to get my wife to agree to going to a resort where nudity was allowed. I kept telling her that if she did not feel comfortable she did not have to be naked at these places. My hope was that I could at least convince her to go topless after a day in the sun and drinking. She eventually said she would think about it so I sent her links to various clothing optional resorts, mostly outside the U.S. to limit the chance of running into someone we know. To my surprise she agreed to go and picked Desire’s near Cancun, Mexico.
When we got there everyone was completely naked. Not a single dressed or topless person. Everyone was completely naked but acted as if everything was normal, hanging out at the pool, grabbing lunch, and playing volleyball. There were no sexual overtones to it. My wife got naked immediately. She actually seemed more comfortable with it than I did. Then came dinner where people got dressed up but in very sexual clothing. Take the same woman completely naked swimming in the pool with no sexual overtones and then put her in a sexy see-thru dress and suddenly it feels scandalous.