My 30 year old husband sometimes has a problem with keeping his penis erect while we are having sex. Sometimes he ejaculates very quickly and other times he has no problems at all. He does drink from time to time, but this happens with or without alcohol. His stress levels aren't to high, so we are confused as to why this happens. He is very embarrassed and isn't ready to see a doctor about it yet. Can anyone help, as to what we can do about this? It's very frustrating for the both of us. Thanks in advance.