A substance produced during anal sexwhen a man sodomizes either a woman or another man and the ejaculate(or cum) of the male (that of the pitcher at any rate) is released into or around the anus(or, loosely, butt) of the other party. The resulting solution is mainly composed of seminal fluid (again, cum) with trace to mass amounts of errant fecal matter(or shit); hence the term "shitty butt-cum." Disambiguated from "santorum" in that it does not additionally require the presence of anallubricants.