If you have the urge to urinate when you press on the small of your back, then the possible reasons are: 1. There is a certain amount of urine stored in the bladder, but at this time there is not much urine and it has not reached the first sensed volume. When you press the abdomen with your hand, the abdominal pressure increases and is further transmitted to the bladder, causing the pressure in the bladder to rise and reach the pressure of the first sensation of urination, at which time you can feel the urge to urinate. It is often seen when about 100ml of urine is stored in the bladder, and when you press the lower abdomen with your hand, you can feel the urge to urinate. 2. The patient’s bladder dysfunction leads to incomplete emptying, such as storing a certain amount of urine in the bladder, but due to weak contraction of the forceps muscle, some of the urine is discharged and some of the urine remains in the body, resulting in excessive residual urine. In this case, when you go to press the abdomen with your hand, you still have urine that has not been excreted. It is recommended that further ultrasound examination of residual urine be performed to rule out such a condition.3. Urine retention due to various urethral obstruction factors, such as prostatic hyperplasia and urethral stricture, is often due to increased resistance in the urethra, and part of the urine cannot be discharged from the bladder and remains in the body. Patients who press the small abdomen with their hands can touch the swelling of the small abdomen and can feel the urge to urinate, mostly consider the presence of chronic urinary retention, and further ultrasound examination is recommended to confirm the diagnosis.