Hi! This is a common problem and usually not cause for alarm. The first step is to rule out a medical problem. A thorough physical examination by your doctor and inspection of the genitalia is a good place to start, followed by a simple urine test (dipstick) that can help rule out a urinary tract infection and to ensure there is no sugar in the urine. If the dipstick is normal, I might suspect holding in behaviour that leads to sudden overflow and release of urine. This is easily managed by reminding the child to take pee-pee breaks and to urinate just beofre bed. Other possible causes are pin worms (does the child have an itchy bottom?) or constipation. Hope this is helpful. Be well. Dr. Jonah Kruger, pediatrician