Pooping can feel good mainly because it relieves pressure and the urge to have a bowel movement. As stool fills the rectum, stretching creates sensations of fullness and urgency. Once the stool passes, that stretching and pressure decrease, which can create a noticeable sense of relief.
A bowel movement also requires several parts of the body to work together. The colon moves stool toward the rectum, while the pelvic floor and anal muscles coordinate to allow it to pass. Nerves between the digestive system, spinal cord, and brain help you sense when the rectum is full and when it has been emptied.
How satisfying a bowel movement feels can vary. Stool consistency, constipation, diarrhea, rectal sensitivity, pelvic floor coordination, and psychological factors can all influence the experience. Research supports relief from pressure and successful evacuation, but it does not clearly show that pooping normally causes a specific release of dopamine or endorphins.
If bowel movements are regularly painful, very difficult, unusually urgent, or leave you feeling unable to empty completely, a gastroenterologist can evaluate possible bowel or pelvic floor problems. Avoid treating persistent constipation or other bowel symptoms with medications on your own without medical guidance.