Watching your wife suck other people's dicks is a buzz kill. And she understands that by licking other people's testicles, her husband's boner will get sharper. So these swinger couples swap to sharpen their senses, bring back the novelty, and make their orgasms brighter. Only I would make the lighting not so bright, then there would be more understatement and less embarrassment.
Just like a goldfish that the fishermen pulled to the shore with a net. How did she know what they had wished for, that she would become a blonde. However, she also had to make her second wish come true - to let them in all her slits. I think she'll get her third wish, too - to suck on a car! So now she has to stay on dry land a little longer than she did with the grandfather from the fairy tale. Because she seems to like sucking and swallowing too!