Christien, 31, says that after waiting six months to sleep with her boyfriend, closing the deal was "intense—in a good way." She decided to wait, she says, because "he showed 'looks like it can go somewhere' potential" and she "could establish a bond with him—both for romance and friendship." But waiting hasn't always been Christien's thing. She'd often slept with guys right away, and the experiences proved to be so-so because "there wasn't that feeling of togetherness."

Bonding has awesome benefits, says Laura Berman: "Research shows that the number-one component of women's sexual satisfaction is not orgasm; it's connection to the person they're with." The more connected you feel, the better the sex will be.

For Christien, this closeness makes for amazing sex because she allows herself to offer and enjoy a full-course experience that includes kissing and oral sex. "I feel more sensual. I don't worry about how my body looks. I already know he's really attracted to me and desires me. I can be relaxed, funny, awkward, all of it—my most comfortable, sexiest self."

What about those women who get busy right away because sex is a part of their mate-appraisal process? (They prefer to know sooner rather than later if the goods are, well, good.) The problem with that logic, says Logan Levkoff, Ph.D., sexologist and author of Third Base Ain't What It Used to Be, is that the first time isn't always representative of what sex will be like: "It can get better as people learn about each other's bodies and speak up about their needs."