Coprophagia is a variation of scat play involving the eating of faecal matter. The prefix 'copro' refers to faeces and 'phagia' refers to swallowing. Thus 'faeces-swallowing'.
Scat eating is often associated with either domination or simply sensation seeking. Scat in its own right has both a powerful odour and powerful taboo/social connotations. Either way, this can make it a powerful draw for many edgeplay enthusiasts as well as dedicated fetishists.
Forced scat eating, either physical or psychosocial, is a form of severe power play where it is seen as the most degrading act possible and therefore the most stimulating, particularly for the sub/slave involved. Its very tabooness, dirtiness and difficulty is often the exciting factor. Frequently, scat fetishists are seeking and usually gaining an extreme emotional trigger for stimulation. A scat high in these circumstances is often better than many drugs, at least reported as such.
As a practical matter, eating scat makes you vomit, and persons into scat understand this, are into it, too. They are also into afterward clean-up, with toothbrushes and sodium bicarbonate.