As a medical professional with expertise in human physiology, I can explain the process that leads to the release of bodily waste after death. When a person dies, the body undergoes a series of changes known as the process of decomposition. One of the initial stages of this process is the relaxation of the muscles, which includes the sphincter muscles that control the release of urine and feces. The sphincter muscles are responsible for keeping urine and feces contained within the bladder and rectum, respectively. When these muscles are no longer under conscious control due to the death of the individual, they relax. This relaxation allows the contents of the bladder and rectum to be expelled, which is why you might observe urination and defecation post-mortem. Additionally, the body continues to produce gas after death due to the activity of bacteria within the gastrointestinal tract. This gas can build up and cause further pressure on the sphincter muscles, contributing to the release of bodily waste. In summary, the release of urine and feces after death is primarily due to the relaxation of the sphincter muscles and the pressure from internal gas production. read more >>

Just like those rare occasions where you laughed so hard you peed in your pants, you will pee and poop in the spontaneous relaxation of your muscles following death. In fact, it's not just the muscles but also the gas produced inside your body following death that will cause peeing and pooping.read more >>