Even though masturbation seems less taboo these days, the National Health and Social Life Survey reported that 58 percent of women don't indulge. And of those who do, 47 percent feel guilty. It's ridiculous, insists Pepper Schwartz, PhD, author of Everything You Know About Love and Sex Is Wrong. "Masturbation prepares you for great sex, since you learn what you like and can teach a partner," she says. Every Cosmo girl should know how to masturbate. Here, a helping hand.