It can, but there's a lot of confusion about what "staying tight down there" really means. When it comes to sex, it's the pelvic floor muscles surrounding the vagina that are key—more so than the muscles inside the vagina itself. During orgasm, your pelvic floor muscles contract; so the stronger your pelvic muscles are, and the better you are at engaging them during intercourse, the more intense your orgasm should be. Having strong pelvic floor muscles may also improve blood circulation to the vagina and can increase your sexual arousal.
Childbirth can fatigue or injure the pelvic floor muscles. Straining when you make a bowel movement or doing lower-body exercises with heavy weights and poor form can weaken these muscles, too.
If you care about powering up your O, there are a few ways to "tone" the correct muscles. The easiest is to do Kegel exercises, which involve contracting and releasing the pelvic floor muscles. First you have to make sure you're engaging the right muscles. When you go to the bathroom, try to stop urinating midstream. If you succeed, you've found the pelvic floor muscles. To do Kegels, tighten these muscles and hold the contraction for 5 to 10 seconds, then relax for an equal amount of time. Aim for three sets of 10 repetitions a day.
Another option: Ask you gynecologist about special pelvic-toning devices that you can insert into the vagina; they help you practice Kegels properly. If you feel you're having trouble with the technique and need one-on-one guidance, ask for a referral to a women's health physical therapist.
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Some women even undergo vaginal rejuvenation: surgical or laser procedures meant to tight the vaginal walls and possibly make the opening of the vagina smaller. Proponents claim the procedure can enhance sensitivity and sexual satisfaction for both the woman and her partner. However, the American College of Obstetricians and Gynecologists doesn't back these surgeries and has challenged claims about their benefits. There isn't enough data yet to determine whether vaginal cosmetic surgeries are safe and effective. Plus they cost thousands of dollars and put you at risk of infection. That's why I recommend going the less invasive (and less expensive) routes.
Health’s medical editor, Roshini Rajapaksa, MD, is assistant professor of medicine at the NYU School of Medicine.