Control yourself!!! 
Rats are cool.
In the psych lab job, I had unintentionally “ruined” a couple of them (part of a group in a behavioral study) by being friendly with them. (We had to pull them from the study.) They’d hunker down comfortably in the crook of my arm and were quite amenable to petting. Also, I could gently hold them under their forearms and stroke their dangling bodies until they relaxed completely and stretched out like spaghetti!. They’d just look at me the whole time, twitching their whiskers. Totally docile!
