Deciphering what she wants in bed is like uncovering the mystery of the Sphinx—only more difficult. Especially considering a recent Johns Hopkins University study reporting that women often struggle to express what they want in the bedroom—and many even have trouble recognizing their own sexual feelings.

Great. If even she doesn’t know her sexual feelings, is there any hope for you? Actually, yes. Use this guide to read her cues in bed.

She says: “Don’t stop.”
You think: “She’s having a good time; I should go harder and faster.”
She means: Don’t change anything—at all.

“When a woman says, ‘Don’t stop,’ she actually means, ‘Don’t vary what you’re doing,’ ” says Pepper Schwartz, Ph.D., professor at University of Washington, and sex and relationship expert for Female pleasure points are very specific. Changing your position—even slightly—can make or break her orgasm, she says.

She says: Nothing.
You think: She’s not enjoying herself.
She means: I’m about to orgasm.

Sure, some women scream like a porn star on Ecstasy—but others will hold their breath and become quiet right before an orgasm. “Many men can think she’s not having fun,” says Schwartz. “But if you change what you’re doing, she could lose her orgasm.” Keep in mind this might not apply to everyone. So if you’re not sure, just ask.

She says: I’ve been masturbating more recently.
You think: Sex with me isn’t enough.
She means: You make me want even more sex.

A study from the Kinsey Institute found the more sex women have, the more they seem to want. See, the more intimate she is with you, the more sexual she feels in general, making her more likely to masturbate. “Masturbation makes both men and women more in-tune with their sexual wants and needs,” says Schwartz. “The more she pleasures herself, the more assertive and confident she’ll be with you.”

Remember: Communication is the key to a good relationship, says Schwartz. So if you’re having consistent trouble figuring her out, talk about it.