Written for comment_fic on livejournal

Prompt was Always room for one more in the Winchester gang.

"Cas." Sam's eyes widened in surprise as he walked into the motel room.

So this is embarrassment, Cas thought. Stupid human body with its stupid reactions.

Sam looked at him for a moment and then said, "You know what? I'm going to go."

Cas sighed. "Wait, Sam. We should talk." Stupid humans with their stupid families.

This was not going to be easy. Cas had been wary of Sam, of his intents, his blood, his power, his role in the demonic plots. He had been so used to thinking of Sam as corrupted and corrupting.

Now he had to explain to this young man why his beloved brother was sleeping soundly after being burdened with the stain of impurity.

Stupid human body with its stupid human feelings.

Cas was supposed to be the one with moral authority. He wasn't supposed to take advantage of his charges, he wasn't supposed to prey on their vulnerability and need for guidance and gratitude for being saved. Not that Dean ever expressed any of those things, but they were there.

And now he was faced with an accuser. Sam. Who had every right to condemn Cas for what he had done. Cas was guilty of corrupting something good and pure. Something beautiful. But so fragile. And yet, in other ways so brightly shining and strong. The fact that Dean had forcefully demanded to be corrupted was irrelevant. Cas now had to face the family of the man whose trust he had abused.

"Sam. I am sorry. I have been defeated by my earthly desires. I am not worthy of protecting your family."

To his great surprise, Sam just smiled at him. "Don't worry about it, Cas. Always room for one more in the Winchester gang. But seriously, dude? They're called pants."