Both mental and physical stress, as well as disease and a number of unexplained factors, can all lead to impotence, and a vacuum pump (used carefully) may help overcome the problem by both boosting your confidence, and increasing the blood supply to the penis. The penis becomes erect because blood is pumped into the penis, and valves close around the veins leading from the penis so that the blood cannot escape. The penis is blown up with blood, rather like a sausage-shaped balloon. There are virtually no muscles in the penis, and so unlike the body builder, there is nothing to develop and increase in size with exercise. A vacuum pump will not increase the size of your penis. There is no simple way to achieve this, but plastic surgeons can perform quite major surgery to increase its size, but usually only in men who have an abnormally small penis. The size of the penis does not greatly affect a woman' s pleasure in sex. How the penis is used, and who it belongs to, arc far more important factors.