Obviously—and thankfully—the vast majority of men learn early that forcing themselves on women is wrong. But pretending to rape a woman in order to get her off is a far cry from actually raping her. "This fantasy has little resemblance to her real desires. Nor does it mean that she's actually been abused or raped," says Dr. Gail Saltz, a psychiatrist and the author of The Ripple Effect: How Better Sex Can Lead to a Better Life—which says that rape is the most common female sexual fantasy. The primary appeal for women, as Saltz sees it, is the concept that "someone would take them at all costs—the idea that 'I'm so unbelievably desirable that he just loses his mind.'" Many experts believe that women use the fantasies to alleviate guilt. "The common theme is that these women somehow feel bad about being sexual," says addiction specialist and radio host Dr. Drew Pinsky. "These fantasies give them license to say, 'I couldn't help myself—I was being raped' as an excuse."

Laura (not her real name), a 26-year-old author of young-adult fiction, was drawn to play out rape fantasies because they offered an escape from her over-ordered life. "I'm so on top of everything all day, so it's a release to have someone else take control and dominate," she says. She's never used safe words or laid out the specifics of what she wants from the role-playing, and one of the three men she's had "rape" her went too far. "He pushed me really hard and pulled my hair, and I wanted him to stop and he wouldn't," Laura recalls. "I wasn't sure if it was still a scene we were acting out or not." According to experts, it's crucial that couples establish boundaries and agree on safe words before attempting to re-create a rape fantasy. Just ask 25-year-old T.J., a stay-at-home dad in Texas, who began regularly acting out these scenarios with his wife. One night she told him that she wanted him to go further, so "I grabbed her from behind and shoved her down," T.J. says. "She was pretty much fighting me tooth and nail." In the process, T.J. (not his real name) found he had tapped into memories of being molested by a couple when he was 12. "I really lost it. A lot of anger and bitterness and rage came up," he says. "And it actually really turned me on to get in touch with that rage. And then I got dependent on it: Now I can't keep it up for regular sex." The good news for T.J. is that his inability to perform has been pretty much a nonissue. The bad? The reason is that his wife "got completely freaked out by what happened—we didn't even talk to each other for a few days afterward," and their sex life has dropped off precipitously.