Many men don't realize their bodies have what's known as a refractory period between ejaculations. In other words, the body simply cannot repeat the amazing physiological performance of erection and orgasm without a little rest first.

The refractory period gets longer as you get older. In an 18-year-Dld, it may last as little as 5 to 15 minutes, but by the time you reach 60, the R&R required between ejaculations is more likely to be 18 to 24 hours. The period varies from man to man-the more frequently a man usually ejaculates, the shorter the in-between period is likely to be.