Not just disgusting, but an inherently dangerous sexual practice.
Actually read an article by an Episcopal priest about how some people think certain parts of the body are “dirty,” and that such thinking is wrong.
He was referring to the termination of the digestive system. The problem is that he is wrong.
That part of the body may or may not be “dirty.” That’s just a word, and definitions can vary.
But from a health perspective there is no question that bringing that part of the body into direct contact with mucus membranes, skin penetrations, the respiratory system or the upper part of the digestive system is a very bad idea from a purely medical POV.
Just as mixing our waste disposal system with our water supply system would be a really bad idea.
In defense of normal heterosexual activity, it has long been pointed out that “the cells which make up the vaginal walls are tough & nodular, and are well designed to withstand the rigors of intercourse & childbirth”.