Erection is a state and process in which the corpus cavernosum of the penis fills with blood and expands, hardens, lengthens and thickens after a man is sexually stimulated, and the process also includes prostate gland congestion, but not only prostate gland congestion. Erection is a normal physiological phenomenon of human beings, the process of erection, generally refers to the male penis by sexual stimulation, blood vessel diastole, blood quickly filled into the cavernous body of the penis, resulting in the cavernous body, prostate, capillaries and other parts of the blood congestion and expansion, the emergence of the process of the penis to support, harden, and become longer. Male penis erection can better meet the needs of sexual life, the process of its erection is the result of the formation of the site, not only caused by the prostate gland congestion.