Sammy was very happy to stay snuggled close to Dean. It made him feel safe and happy. Dean was a safe place, a warm thing, a happy feeling.
So when Dean put him down and suddenly his butt got cold, Sammy squawked and flailed because his butt was not meant for cold and now it was wet! WET! Wet was NOT GOOD. Sammy's fists balled up again, for the love of humanity! He wailed.