Like with most psychological phenomena, there's no direct explanation for why some women are turned on by the notion of force while others are aroused by the idea of making love in a field of daisies—only speculation. "I believe it's related to childhood experiences of being reprimanded or controlled or overpowered," Saltz says. "Early, primitive feelings of aggression are often wrapped up with libido." That might explain the case of 34-year-old Nicole (not her real name). "When I was growing up, my parents really made me feel like my emotions made me unlovable," she says. The rape fantasy appeals to her because, she says, "it's like someone's angry or unhappy with you but still paying a lot of attention to you—as opposed to in real life, when, if you're acting unlovable, people just leave you alone."

Regardless of what gives it allure, the rape fantasy is a powder keg of sexual politics. Common sense dictates that you always consider worst-case scenarios when deciding whether or not to duct-tape a woman's mouth shut as she begs you to stop. Although Josh (not his real name), a 28-year-old from Mississippi, didn't end up in cuffs after he followed his then girlfriend's directions to break into her house and hold her down during rough sex, he's aware that he could have. "About a year after that, she attacked me when I tried to stop her from going after her mom with a kitchen knife," he says, adding that his ex was bipolar. "When I was fulfilling her fantasy, I was in that early, puppy-dog-love stage, where I would have done anything to please her. It was only later that I realized I could have really gotten into trouble."

Ironically, according to some experts, it's an increasing problem that many men are not educated about their right to draw the line. "You don't want to be in a position where you're going to be doing something that's really horrifying to you," Saltz says. "Keep in mind that you can always say, 'Let's go carefully' or 'No.'" Now men who understand that no means no just have to hope that women do too.