Penis to shrink back may be the environment temperature is low, obesity and other physiological factors, or circumcision, hidden penis and other factors. 1. Physiological factors: If the surrounding environment temperature is too low, obesity, may lead to the penis naturally shrink back, is a normal phenomenon. Do a good job of keeping warm and actively lose weight, can be relieved. 2. Hypospadias: Hypospadias may be caused by factors such as penile dysplasia and narrowing of the opening of the foreskin, which may result in the head of the penis not being able to be revealed, or the tribes revealing it, which is manifested as the penis shrinking back. 3. Cryptorchid penis: cryptorchid penis is caused by obesity, abnormal development of penile lining, abnormal penile anatomy, surgery and other factors. Patients show that the penis is short when lying down, and the circumcision opening and circumcision cavity are narrow, which is manifested as retraction of the penis. There are many reasons for penile retraction, and it is recommended that patients find out the causes of the disease in time and actively take relevant treatment measures. In daily life, we need to keep the penis clean to avoid secondary infection.