According to Dr. Dannoff ....
Here are five changes to be ready for as you age:
It takes you longer to get an erection. This might start happening to men during their twenties. It might happen so gradually that it is not even noticed until they approach middle age. At some point, men discover that it takes more stimulation to get them hard. Once your testosterone levels diminish with age, fantasies, the sight of a sexy body, and even heated foreplay may not be enough. It might require a little more direct stimulation from your partner. Many older men can only get an erection from the vacuum effect of oral sex and the psychological aspects associated with that sexual act.
Your erections are not always as rigid as a steel rod like they were during your teenage years. Sometimes they are only half-hard or semirigid until added stimulation hopefully brings them to full strength. This, too, is normal, but men often greet this phenomenon with panic, recalling the days when they seemed to spend half their time concealing their erections.
It takes you more time to be ready to go again. It is a well-documented urologic fact that the amount of time it takes to recover after an ejaculation increases in proportion to a man’s age. When a man reaches his fifties and sixties, the refractory period might be as long as twenty-four hours, even with direct stimulation. At age eighty, it might be one week.
The amount you ejaculate decreases. Just as the refractory period increases with age, the volume of the ejaculate decreases. Men also notice that the ejaculation itself feels less and less explosive as they age; the semen leaks out rather than being forcefully expelled. Orgasms might also feel less intense.
It takes longer for you to reach orgasm. As the old joke goes, “It takes all night to do what I used to do all night long.” This may not be a problem, especially if you found it difficult to control your ejaculations in the past. Young men who were quick on the trigger find their sex lives more satisfying when they reach the age when delaying orgasm is not a chore but a natural process. If your partner is a woman, she may even get more pleasure because it is usually easier to bring a woman to orgasm with prolonged intercourse than with quick encounters.