I would question why your sexual connotation leans toward the ingestion of fecal material.

Since this is often said amongst males one would assume your postulations would veer toward the homo-erotic. :party0048:This would be the easy corollary to draw but you so eloquently choose "scatological aspersion". Purchance have you viewed 2 girls 1 cup too many times?
Personally I use it to refer to what some one should do with that next shot of tequila

or to do their duty even if they dont like having to do it.