Hard On Demand PDF eBook download, by Brad Stevens. Why does a man have problems getting an erection? There are many possible reasons. The most likely problem can depend on age and experience. First and foremost, a strong erection requires good blood flow. Try to eliminate everything that decreases blood flow like smoking cigarettes, doing illegal drugs, drinking too much, and being under a lot of stress. I found an article at DonnaJeanBooks that is pretty short and to the point. I hope it is helpful. Spice up your sex life. Increase your manhood 2-3 inches both in length and width. Increase stamina and endurance. Get stronger erections and stop premature ejaculations.