I would say 90% of the male clients I see have had trouble getting and maintaining erections on a regular basis. There are a number of things that can cause this and some are physical, so my first task was to eliminate the physical causes, which would leave only the emotional/psychological. And even here there can be many underlying causes, but if a man has a smaller than average sized penis, there's a good chance I can work with him to get his cock at full attention.
One client was a young, attractive, successful businessman. He had a number of women who pursued him, but as powerful as he was in the world, he was utterly withdrawn in the bedroom. His erect penis measured 3.5 inches in length and just a tad over 3 inches in girth (one of the smallest I had worked with). When he was in high school, he had been humiliated by a girlfriend and she wasted no time in spreading the rumor of his underendowment.
This deeply affected him and ruined his adult sex life. When he came to me he had had a series of short relationships with women. The relationships ended in the bedroom -- not because of his size, but because of his utter fear of exposing himself. He would never let them touch it, would never take it out of his underwear until he was fully erect. But each time, instead of growing, it shrank even more. He said it was worse than what happens when it's cold.
In my office, I measure all my male clients, but I wasn't able to that first visit. His penis retracted beneath his pubic hair so that all that was visible were his testicles. It took several office visits where I had to dig deeper and get him to open up about his experiences before I was able to measure his penis. He ejaculated just as I was measuring his girth. He said it was the first time he'd ever been brought to orgasm by another person.
He had a lot to overcome and sometimes just expressing it -- talking about it -- can make one accept tragic experiences and finally come to know that they are in the past.
He finally met a woman he felt he could confide in. After telling her everything, she took on the role of nurturing lover. He said later it took about a week before he was confident enough to achieve a full erection and have a normal sex life with the woman who would become his wife.
If you have this problem, sometimes it's best to open up and communicate with a potential lover. She should know ahead of time that you feel you have a small penis and this sometimes prevents you from achieving an erection. If she laughs and breaks off the contact, then she wouldn't have been accepting of you or your penis in the first place. But if she stays and takes on therole of a nurturing, understanding lover, then all you have to do is communicate, caress and touch.
She'll do the rest.