When Juan hears Trixie, a 48-year-old wife from Ohio, talking on the phone about going to a swingers club, he’s intrigued. “My girlfriend really doesn’t know about that, and I’ve always wanted to talk to her,” he says. Trixie has a plan. “Why don’t you bring her by tonight, and I’ll have a talk with her?” she says. “I’m really good at turning vanillas.” Flash-forward to a few hours later. Trixie is dressed…