One of my last classes at school concerned the lower GI tract. Specifically, the anus and what comes out of it. So, whooooo! GUAIAC test cards, otherwise known as a fecal occult blood test, were passed around. It would be a lot more interesting if it tested for magickal, fortune-telling bloody shit, but no, it just tests for hidden (occult) blood in the stool. Usually indicative of a problem.
Our instructor, a very enthusiastic person even about fecal occult blood tests, asked, "Has anyone done a GUAIAC in their clinicals? Nobody has done a GUAIAC? Oh, you’ve missed out on some real fun."
Err, yes, real fun. Just what we were all thinking.
Then she hauls out a piece of medical equipment called a hat, though you do not want to put one on your head. They look like this (upper right corner)
and they are for assessing urine and fecal output (yeah, we say output). So she's waving this around and it's clear that there is a brown mass contained within. “Don’t worry," she says, "It’s just frosting.” So there goes the idea of chocolate for at least the next few days.
While running us through the procedure she notes, “And you’re breathing through your mouth.” Of course, everyone in the classroom is well aware of how odors actually work. Little tiny particles of whatever you're smelling go right up your nose. So breathing through your mouth is not really better, per se. Like many things involving the body, it's best not to dwell on the aesthetics.