"Scat", a noun meaning dung or excrement, particularly that of an animal. It is not a new word, by any means, and its use is not limited to discussions of sexual fetishes.

"Scatology": 1. The study of fecal excrement, as in medicine, paleontology, or biology. 2a. An obsession with excrement or excretory functions. b. The psychiatric study of such an obsession. 3. Obscene language or literature, especially that dealing pruriently or humorously with excrement and excretory functions.

The origins of the word are unknown, but it has been used for centuries.