A large number of studies have found that people’s control of the penis is limited compared with other parts of the body, because the penis does not always follow the control of the nervous system, but is also subject to the “autonomic nervous system”, also known as the leader of the autonomic nervous system. The latter is also responsible for regulating heart rate and blood pressure. Many sexual arousal is the “credit” of the autonomic nervous system. For example, during deep sleep, the pulse from the brain can induce erection, lifting weights and abdomen lifting can also promote penile erection. It can get smaller when you can’t think of it. Dr. Montag, a US urologist, pointed out that exposure to cold water or air would cause the penis to shrink, and psychological stress could make it weak. These are all governed by the autonomic nervous system, so the penis can also be considered a “barometer of the autonomic nervous system.” It will also break. Although there is no bone in the penis, it can still break and make a sound, then it becomes blue and painful. This situation mainly occurs in young people. The typical case is that the man is too hasty and the result hits the partner’s pubic bone. To avoid this, don’t be too rude when you are sex.