Couldn't resist writing another one. Next season in so close!

This one happens before Lucifer got out of it's cage, even before Uriel's death, actually.

I hope you enjoy.

What is in a nickname?

"Cas."

What kind of calling was that? Was something wrong with his name? And, most of all, why was he worrying that much with the way Dean was calling him when he had other more important questions? It was already bad enough that he had questions, in first place. He could not let himself be troubled by that, he needed to trust in his Father's Word and remain with peace.

Inner deep breath. Even though he didn't need to breathe.

"Cas."

Still, it was all it took to bring questions again. A mere part of his name and any peace he could gather was sent far away, as if there was some spell in that voice. Whatever it was, it was strong enough to make him wonder if it was not some sort of test.

But why being tested? Was it fair? To test his faith as if he had done something against the Lord or any of His creations?

There were the questions again.

"Cas!"

Uriel had smirked at him the other day because of that. Warned him, actually, that if he let the "mud monkeys" call him that way, soon they'd be thinking they were allowed to boss him around.

Not that Dean Winchester needed a nickname to do that, he already bossed around everyone if he was not put in his place.

"Castiel?"

"Yes, Dean?" he finally answered, turning his stare from the window to the three of them.

"Hey, glad to know you're here with us, for a second a thought radio angel was way more interesting than humans talking about Apocalypse. What do you guys hear up there? Stairway to Heaven?" the older Winchester said with his classic smirk "Or should I guess that the problem was calling you Cas? Angels don't like nicknames?"

"What is in a nickname?" he asked, truly curious, looking directly into the hunter's eyes.

Obviously his question caught them surprised. Samuel and Bobby both lifted their eyebrows and looked at Dean, who was staring at him as if he was crazy.

Sighing, Castiel turned to look at the window again.

"Answering your questions, 50 seals have already been broken. Lilith is being fast, you must hurry as well. We believe her next move is to burn five hallowed grounds, this is the next seal. You must stop her."

They continued to discuss the situation, began to make their plans. Not all of them. Now Dean was staring at him as if he was suspicious of something.

Questions kept rising.

Later that night, Bobby and Samuel were soundly asleep, taking every thing they could from a good night of sleep before they went to meet another battle against demons. Dean, however, was wide awake looking at the ceiling; Castiel didn't need to be in the room to know that. He just knew. And wondered how he could be so sure about a human and at the same time have doubts about the Lord, about his own Father's plans.

It was not with great surprise that he heard Dean walking into the yard to stand by his side.

"So, wasn't your cloud comfy enough?"

"I don't have a cloud." He answered simply, quirking his head to the side, trying to wonder why on earth would Dean think he'd have a cloud. Then he noticed the face the hunter made.

"Yeah, yeah… private property is very expensive these days, one with view to the Earth must cost your soul, huh?" Dean continued with the joke, waving his head in amusement at Castiel's lack of sense of humour.

"So, what is going on with you today? You seemed to be off the whole conversation. Tell me, Cas. Or… should I call you Castiel?"

Was Dean insecure about how to call him?

"You can call me the way it suits you best."

"Oh, ok."

Castiel knew that Dean used to give nicknames for everyone. Sammy for his brother Samuel, Junkless for Uriel, Cas… It was a very human thing to do, a human way to be closer or farther from others, a very intimate way. Now what did that tell him? The hunter wasn't one to enjoy intimacy unless it involved flesh and certain needs.

"I understand that humans like to give each other nicknames for various reasons. I cannot understand the process, however."

"What do you mean?"

"You call Uriel something considered offensive in your kind. My nickname says nothing, though. And we are both angels, we are both from a kind you don't like."

Dean stared at him for while before making himself comfortable against the nearest car and looking to the sky.

"Well, there really isn't a process. One day the nickname just comes out, if it's good, it will catch and people will start using it… or sometimes only the person who created will use it to call you, as in a way of proximity…"

That didn't tell much. Bobby and Samuel also called him 'Cas'. Did it mean that it was a good nickname but not a way of proximity? Somehow that thought didn't please him that much, he would have liked it better if no one else called him 'Cas' and it meant closeness between him and the older Winchester brother. Castiel simply watched Dean watching the stars and was almost surprised when the hunter suddenly focused on him.

"Why do you ask anyway? Does the nickname bother you? I mean… I could stop calling you like that."

"No." was his immediate answer and now he was truly surprised by the urgency he had felt. Turning to look ahead he said "It does not bother me… do not… do not stop calling me like that."

He didn't need to look at the hunter to see a half smirk half smiled being formed – more smile than smirk and somewhere inside his body Castiel remembered he had a heart in his vessel. "OK." Dean answered and returned his look to the night sky "If you want, you can nickname me as well, I don't mind."

Castiel thought about the proposition for a moment. It made him wonder. What could that mean? Was that some kind of privilege just for him? Not even Samuel called him anything, but why was that?

"No one else has a nickname for you. Is your name hard to turn into a nickname?"

"It's not just about the name, it's about the person as well. Some people call Sam 'Grumpy', you know, because he is always brooding and scowling at good things like… like pie and good horizontal activities, if you know what I mean." Dean smirked at him at that last part, but it was obvious that he didn't expect the angel to know what he meant by that.

After a few seconds of consideration, Castiel had some ideas.

"Then would 'Libertine' suit you?"

The hunter gasped.

"Is that the first thing you think about when you think of me?"

Castiel looked at him even more confused. Dean hadn't said anything about the first thing you think of when you think of the person. He had never thought there would be so many rules to call people other ways than their names.

"I don't have a word for the first thing I think about when I think of you."

"Oh." For some reasons that picked the Winchester's interest "And why is that?"

"Because it's an action."

"What action?"

Later on, Castiel would realize that things could have gone very wrong at that moment. However, had he not been so clueless and lacking of people skills and human habits, maybe things wouldn't have developed – and maybe he wouldn't have learned how to give nickname to people.

Either way, when Dean asks something, he usually answers as truly as he can, and in such a time when he's being forced to lie so much to his hunter, he liked to compensate in the things he could answer. So, as soon as he was asked, Castiel leaned forward and planted a kiss on Dean's lips.

That was another of his questions. One that had nothing to do with the art of nicknaming, but somehow had gotten mixed into the matter, now that he knew the rules of inventing one.

And then, when Dean began to kiss him back – and taught him how to, for that matter – Castiel finally had a moment of peace in his mind and soul. All the things that had been ramming in his head, screaming for him to understand them, were silenced as he learned to move his lips and tongues with Dean. Soon after the peace was substituted by something different, something that reminded him of explosions yet that it seemed to be really good, and in the midst of all that, he found joy in a beating heart somewhere in his body.

On that same night, Castiel learned other human things. He got new questions, and even though he knew that on the long run that would probably give him new doubts about the whole ordeal, for now the answers he got about Dean were more than enough to keep him sane and happy.

At least, he could say he had found a good nickname to call the hunter. But Dean had told him that he should not tell other people, that only he was allowed to use that. Castiel was not sure why, he just assumed it had something to do with dominance displays or some of those complicated human concepts he would most likely never understand. He didn't care, really. Dean was good at giving answers. And at kissing too.

Thank you for reading. Review if you feel like it.