When a person (or animal-- see below) defecates directly into the anus of a willing sexual
partner. This is accomplished by both partners getting on their hands and knees, or laying on their backs with legs in the air, with their buttocks
pressed together. With a lot of patience and experience, an expert pitcher and catcher can oftentimes maintain a back-and-forth for hours of
pleasure.
It is widely debated whether or not the Tootsie Roll Exchange happens in nature, or if it is a man-made creation; this has caused a rift in the animal sex-science community, spurring many heated arguments, and even one
slap-fight at the annual Animal Sexuality-Science Convention in Zurich (citation needed).