That reminds me of my First-year at Med School. We were receiving our first anatomy class with a real dead human body. We all gathered around the surgerytable with the body covered with a white sheet.
The professor started the class by telling us, "In medicine, it is necessary to have 2 important qualities as a doctor:
The first is that you not be disgusted by anything involving the human
body."
For an example, the Professor pulled back the sheet, stuck his finger in
the butt of the corpse, withdrew it and stuck it in his mouth.
"Go ahead and do the same thing," he told his students.
Some of the students freaked out, hesitated for several minutes, but eventually we took turns sticking a finger in the butt of the dead body and sucking on it.
When everyone finished, the Professor looked at us and said, "The second most important quality is observation. I stuck in my middle finger and sucked on my index finger. Now learn to pay attention.