Male erection, as the name suggests, is a state in which the penis becomes thicker, larger, and harder after external stimulation or psychological intervention. This is a condition that occurs when the arteries dilate to increase blood input and the veins constrict to decrease blood return, allowing more blood to accumulate in the vascular sinuses of the penile corpus cavernosum. The erection of the penis is a normal physiological change process that normal men should have, the erection of the penis may appear in several situations: first, after being stimulated by a variety of external stimuli appear a physiological erection; second, in the sleep of a sleep state of erection, many people may also be concerned about the morning erection when waking up. So, erection is a normal physiological process that every normal male should have. The problem of erection can occur in two ways: one is impotence, also known as ED, which is an abnormal erection state; the other is an abnormal erection of the penis, if the erection time is too long, let’s say 4-5 hours, after erection after sex or masturbation after ejaculation can not be weak, must go to the hospital to see if there is an abnormal erection, otherwise Without timely examination and treatment, the best treatment time may be delayed, leaving behind some cases of erectile dysfunction in the future.