Still armed with adolescent energy and high testosterone levels, men in their 20s often seem on a mission to have as much sex as humanly possible. And the institution of marriage -- with all its possibilities for romance and spontaneity -- lends itself perfectly to this quest. While your husband's single pals may still be gathering sexual experience with lots of women, your husband is looking to do his exploring with one person -- you. "It's a time of proving oneself, and although there's a lot of emphasis on the quantity of sex, there's also a lot on the quality -- he wants to feel that he's good in bed, that he knows how to please you," says Sharyn Hillyer, a sex therapist in Beverly Hills, Calif.

Good sex, defined by these guys as frequent, orgasmic, multipositional athletics, remains an absolute necessity. Mark, 24, estimates he has sex with his wife about once a day, and admits that if the sex weren't mechanically as good as it is, his relationship would be difficult to sustain. "I think sex is very important in maintaining intimacy," he says. "If you're not sexually compatible, sex will become a chore, and you're not going to be as attracted to one another."

For a wife trying to improve a sexual relationship with one of these guys, quantity is a good place to start. Nothing will endear you to a young husband more than being open to sex at any time of day or night: in the car, on the kitchen counter, even in one of those aptly named service elevators. "I'm pretty much always ready for it," confesses Edward, 26. "The only thing I'm concerned about lately is making the experience last longer."

Making the experience last longer -- that's the downside, in a nutshell: What good are 17 1/2 orgasms a night, when each is over in 30 seconds flat? Premature ejaculation is the universal curse of young bucks, and it's the source of much angst. "They get excited easily and don't know how to identify the point of inevitability before ejaculation," says Richard Cohn, Ph.D., director of the Siren Counseling Center and Sex Clinic in Los Angeles.

The problem, of course, is overstimulation. Remember, at this age everything (from underwear ads to magazine scent-strips) is a turn-on. "I can get an erection just sitting there thinking about sex," says Jason, 27. "Sometimes a girl can walk by, and just the perfume gets me going."

Part of that sensory overload is coming from you. If you want to improve the sexual experience for your hubby, make it easier for him to hold back. Limit your foreplay to light brushes over the genital area. Keep your ministrations brief -- linger in one area too long with too much baby oil, and you risk bursting the pinata before the fiesta begins.

Another way to help him delay his big O: sex with you on top. It's less directly stimulating, and hence easier for him to maintain for the long haul. Switching positions can also help him regroup. Just beware of doing anything dangerously erotic: Move slowly, and stop if he indicates you've brought him close to the edge. Another strategy: The first time of the night, set him off without requiring that he "wait for you." Then, kick back and wait a half hour -- he'll be randy as a goat before you even get drowsy.

And what if you find your enthusiasm lagging behind his for whatever reason (say, if you've just had a baby and your body's not back to normal yet, or you're just too darn tired)? Because the sexual appetite of men in their 20s is more fast food than gourmet, you don't have to feel pressured to gear up for hourlong sex every time the guy's eyes light up. Believe me, you'll make him just as happy with a quick manual or oral (oh please, oh please) servicing, particularly if you make it clear no reciprocation is required. You'll be back to your novel before the plot gets cold, and he'll be on cloud nine. This is the phase, after all, in which men say and mean things like, "Even when sex is bad, it's good," and "I never met an orgasm I didn't like."