In LOST, when a character places a
handgun in the back of their pants, they risk exposure of
fecal molecules to the gun. Later handling of the
firearm could then spread said fecal matter to hands, and in turn to eyes and/or mouth, causing illness or infection.
Kate:"Wow,
Sawyer, looks pretty sick after waving his gun around."
Jack:"I think we have an acute case of Poopy Handgun Syndrome on our hands. Literally, on our hands."
Kate:"Gross. I'm not banging that dude in the bear
cages again. How do you know it's
PHS?"
Jack:"Cause I'm a God Damn Doctor, that's how!"