Some couples play dress-up even when it’s not Halloween; imagining different people and scenarios while making love can invigorate your sex life—or it can make you feel a little creepy. How do you get the best from your fantasies? Here’s a guide to navigating your sexual imaginations. "From picturing the hottie in Accounts Payable naked, to role-playing, to thinking about other people or circumstances while masturbating or having sex, people often use fantasies to augment their lovemaking. In fact, there are women who can achieve orgasm merely by conjuring that philanthropist/mailman/pool boy/plumber in their heads. (Seriously. And they're being studied.) Even if you're not blessed with that ability, research has shown that women's orgasms are in some ways more tied to mental gymnastics than to anything that's happening in the physical world. 'In women, the vast majority of sex is going on in their minds,' explains Dr. Anita H. Clayton, a professor in the Department of Psychiatric Medicine at the University of Virginia and author of an upcoming book about the relationship between sex and the psyche. 'So we can be easily distracted or shift into another set of feelings very quickly.'"