Sexpertise is cheaply won; there's a lot of bad, regressive sex advice out there, and it's sometimes hard to sort the wheat from the chaff. Let us assure you that Dr. Debby Herbenick isn't your regular sexpert. Besides toting around a vulva puppet and running the website mysexprofessor.com, she's an honest-to-God scientist. She's not called a doctor for nothing: she's the associate director for the Center for Sexual Health and Promotion at Indiana University, and sexual-health educator at the Kinsey Institute for Research in Sex, Gender and Reproduction. Her new book, Because it Feels Good: A Woman's Guide to Sexual Pleasure and Satisfaction, will surprise even the most sexually enlightened women with its insights on their bodies, sex, and how to get the most out of bedtime playtime. — Jen A. Miller

What are the two things most women, even those super comfortable with sex, don't know about their bodies?
How easy it may be for their bodies to stay aroused. Women may be in the middle of sex and then their partner uses an unpleasant technique or they think about something unsexy (like the laundry) and they worry that they have "lost" their arousal and can't get it back. Although it may feel that way, women's bodies actually stay in an aroused state for several minutes. If they can try to re-focus on what feels good, they can likely get their arousal back on track and be closer to orgasm than they realize.

Women also often don't realize how adaptable their bodies are. Even though they may have found a position that pushes their orgasm buttons every time, that doesn't mean it's the only position that will work for them. I like to encourage women and their partners to take breaks from their routine and try something new — try oral sex squatting on your partner's face rather than lying on your back; try woman-on-top squatting rather than kneeling; try giving your partner oral sex for ten minutes longer than usual before jumping into the next activity. Then, take note of what you like — how did it feel to do things differently? Is there something you tried that gave you pleasure, made you want wetter or more excited, or got you closer to orgasm in an unexpected way?

Do women underestimate the role that a mental connection plays in good sex?
Yes, and men, too. Research has consistently shown that the psychology of sex is as important as the physicality of sex. Women can use mindfulness training to enhance their sexual desire and arousal. They can also re-frame negative thoughts into positive ones in ways that enhance their arousal and make them feel more excited about sex — for example, rather than thinking, "Here we go again, he's always pressuring me to have sex," she can think, "He thinks I'm hot, sexy, and practically irresistible." Talk about a change in perspective! Negative thought patterns make people dread sex; positive ones can help people to embrace sexual intimacy, connection and pleasure.

How do our ideas about sex change the most as we age?
Sex and aging are interesting. Although erections get softer and less reliable with age, and vaginal lubrication decreases (as does desire), sexual satisfaction tends to remain fairly high. It may be that women and men develop more realistic expectations that are thus easier to meet as they age. We also know, however, that women and men tend to appreciate emotional closeness as a part of sexual intimacy in ways that they may have perhaps overlooked when they were younger and more focused on the physical side of their sexual performance.

What are some surprising erogenous zones?
I'd contend that the mind is one of the most overlooked erogenous zones — dirty talk and sexual fantasies can greatly enhance sexual desire, arousal and orgasm for many women and men.

Also, I like to encourage women and men to make small changes — sure, the clitoris is a known hot spot, but what about the area just an inch or two away from the clitoris? What about the inner thighs? Or the sides and tops of the breasts, and not just the nipples? These are all sensitive areas but people often zoom in for the kill, rather than the seductive process.

What myths about women and sex can we finally throw out the window?
That "good girls" don't want — or initiate — sex, and that women don't masturbate or aren't "visual" creatures.