Gabrielle: "Don't be a know-it-all. Those are the worst, and they are talked about the worst."
Here's reason to relax: Your personality and your chemistry with her are more likely to be discussed than how you performed sexually. "I'll tell my friends if a guy is playful and fun and doesn't take things too seriously," says Janna, 23. Miriam, 21, concurs: "We bitch if a guy doesn't have a sense of humor."
Win her approval: Lighten the mood. "Laughter, in some ways, is like an orgasm," says Janice Levine, Ph. D., a psychologist in Lexington, Massachusetts, and the editor of Why Do Fools Fall in Love?"It helps release the tension that can come with first time sex." If matters don't proceed smoothly in bed, laugh it off without making any cracks about her specifically. Sarcasm can be taken the wrong way.
Gabrielle: "I'm not saying you need to look like a Crest commercial, but I hope you floss."
You and your buddies aren't the only ones who discuss superficial appearances. "God forbid he doesn't take care of himself -- we rip on him," says Jenni, 36. Your gym time will pay off, too: "I'm going to want to brag about how hot he is," says Victoria, 28.
Win her approval: Of course she wants to be attracted to you. "But it's also important to her to convince her friends that the man she's had sex with is good-looking," says Gordon Patzer, Ph. D., author of Looks: Why They Matter More Than You Ever Imagined. If her pals lust over you, it boosts her ego. So think clean -- clothes, body, scent. Being in shape is important, but a recent survey by the research firm Synovate reveals that poor hygiene can detract from even the most ripped set of abs.
Gabrielle: "Nobody wants to feel like just a vessel. You want equal participation, so it's not '68 and I owe ya one.' "
Pay attention to her desires. "This is big to me," says Ashley, 25. "It makes me feel less used, so I let my girls know." A chorus of women echoed her sentiments. "This speaks to more than just sex; it's about how we connect," says Karen, 32. For Kelly, 27, it's a barometer of character: "It makes a man seem very sweet if he's attentive, and like a selfish jerk if he's not."
Win her approval: We don't want a wimp. "Some men think they're being attentive, but they're really being tentative," says sex therapist Sandor Gardos, Ph. D., the founder of MyPleasure.com. "They touch her hesitantly and wait to see what she does. That's not very sexy." Be confident, not aggressive. Make your moves without apology, but watch and listen to gauge what she likes. Or just ask!
Gabrielle: "If it's a choice between a man who gives flowers and a man who enjoys giving oral, most women would take the oral. And it's free. Oral sex is recession-proof."
Women will dish whether you're awesome or awful. But at least try. "There's nothing more disappointing than a man who doesn't try or is just clueless," says Katy, 28. "If he's great, I'm thrilled and want to spill to my friends. If he was terrible, I want someone to sympathize."
Win her approval: Be eager. "It makes a big difference if you're showing authentic enthusiasm. Women read that," says Gardos. Michelle, 25, told us that she and her friends compare notes on "how involved he was" during oral sex. Too many men focus only on intercourse, Gardos says. But a 2006 Australian study found that far more women are able to reach orgasm with oral sex than through intercourse alone.
Gabrielle: "If both people can climax quickly, sex doesn't need to go on for 2 hours -- at some point, Law & Order is coming on! But it's terrible if a man is 2 minutes and you're nowhere close."
Breathe easy, men: If you don't last long, women are generally forgiving -- provided you make up for it. "Only if things ended immediately afterward would I ever say he didn't last very long," says Victoria, 28. "If he's a one-pump and done, it does get talked about," admits Janna, 23, "but if he makes up for it later that night or in the morning, I'll have only good things to say." And again, personality matters: "If we like him, we make excuses for him," says Paula, 20. "If we don't like him, we make fun of him. Harsh, but true."
Win her approval: If you climax quickly, resist the panicked urge to explain. (We see through the classic, "This never happens to me, I swear.") "Instead, make it about how sexy she is and how much she's turned you on, not about how you aren't in control," says Herbenick. Then make sure she gets her turn.