Helo over at Drumwaster's Rants just got his first taste of Pepper Spray.
Back when I was young, dumb, and a member of the Army Military Police Corps, I got to go through that wonderful thing known as Pepper Spray Training. Learn about it, watch videos of it in use, and then get hit with it. Because you can't use it if you don't know what it feels like.
What it feels like is a dozen blowtorches being lit up and held directly against your face. What it feels like is burying your face in a fire ant nest. What it feels like is dunking your head into a vat of hydrochloric acid.
Ever accidently rubbed your eyes after cutting peppers? Multiply that. By a million.
Anyways, go read his description. It's pretty spot on, especially the after experience shower.