The penis shrinking to a little bit after a bath may be due to the influence of the lower outside temperature, causing the spongy body of the penis to retract. When the temperature of the body surface drops after a bath, the blood circulation in the testicles decreases, causing a decrease in blood flow to the corpus cavernosum of the penis, leading to penile contraction, so the penis shrinks to a little bit. When the outside temperature rises or after being in a warm environment, the penis can return to its normal state, so this situation belongs to the skin’s natural adjustment state and does not require any treatment. In daily life, before and after sex should pay attention to clean treatment, maintain personal hygiene and cleanliness, but also can carry out appropriate physical exercise, improve the body’s immune system, if the patient has a circumcision and phimosis, the need for timely surgical excision treatment.