I like to use metaphors to get my point across.
So I told Matthew, "When you make Nolan cry, it affects your Mom and Dad mentally and physically. It is like taking your fingernails and scratching the surface of a chalkboard." I motioned my fingers going down the chalkboard and cringing.
I got a blank stare. Deb joined in, "They have dry erase boards at schools now."
I thought for a second, and because I recently had a flu shot I decided to use that as the metaphor.
"Ok Matthew, making Nolan cry is like getting a flu shot. Instead of getting one of those thin needles you get one that is an inch thick."