So, Cass was human. Dean could learn to deal with that. Dean could help him explore the awesomeness of being human. He could teach Cass about pie, and cowboy movies, and cars, and music, and everything. What Dean didn't think was an important lesson was sneezing.

The three of them, Cass, Sam, and Dean, were sitting in their motel eating takeout and watching the cheesy western that was on. Dean heard a sneeze and tossed a napkin towards Cass without looking up from the screen.

"Dean…." He looked up to see Cass' startled expression.

"What's up, Cass?"

"What was that?" it took Dean a minute to realize that he meant the sneeze. Of course he meant the sneeze. It was his first one. Cass' eyes were huge with wonder and his hand was touching his nose in bewilderment.

"That was a sneeze, Cass."

"I can't tell if I like it or not." He wrinkled his nose and sneezed again. It reminded Dean of the video of a kitten sneezing Sam had shown him. Dean laughed. One of the laughs that throws his entire body back. Sam smirked a little without looking away from the screen and Cass sat there confused. Cass doesn't think he'll ever get used to being human.