A Mature Solution

Caitlyn:  Mama, Alex pulled my hair, so I made a sign.
Mama: What does the sign say?
Caitlyn: It says "Stop Pulling Everyone's Hair"

A few hours later: Alex pulled Mama's hair.
Caitlyn:  Oh, I will get my sign......
Runs and grabs this:

and it holds it up for Alex to see
Caitlyn:  See, Alex, the sign says "Stop Pulling Everyone's Hair"!