The presence of faeces or the solid waste matter or the stool in the rectum of the body triggers a reflex that facilitates the elimination of the wastes from the body. Peristalsis is the process that helps move the stool into your rectum. Rectum is the lower end of your large intestine. The rectum stores the stool until it pushes stool out of your anus during a bowel movement. The bowel movement is the opening of the anus and the contraction of the bowel muscles to push the stool out of the body.