icky subject, but basically the bowel turns itself inside out like a finger on a rubber glove. So what you see hanging out the tail end is looks like a loop of bowel but is actually the inside of it. It can be reinserted, and stitched in place if necessary (by going in surgically) but it is a tricky thing as the bowel is in constant movement (muscle contractions called peristalsis) and so it can evert again without too much effort. Soft semifluid food with no roughage was recommended way back when I was involved in this sort of thing but things may have moved on since then.
