After a man has ejaculated, his penis usually becomes soft and shorter again. He may also have an enjoyable and relaxing feeling in his groin area. It takes some time before he can have another erection and ejaculation. This time is called the refractory period. The average refractory period is about half an hour. Younger men normally have a shorter refractory period than older men. Men who are 18 years old have a refractory period of about 15 minutes, while men in their 70s have one of about 20 hours. Some men's penises remain hard after one ejaculation, and they are able to have another ejaculation after some time without losing their erection. Most young and middle-aged men can probably have about two to three ejaculations in a few hours, but it has been said that some men are able to have up to nine ejaculations a day.