Somehow, Cas's finger always seems to hit the button for Dean Winchester on speed dial.

When he first hid them from all angels, including himself, he had experienced mild panic. Not being able to know where Dean was at all times was... not ideal for him. (he told himself it was because he wanted to keep track of Micheal's vessel.) So he'd gotten a cell phone and programmed Dean as number one, Sam as number two. (he told himself it was for the sake of alphabetical order.) And he always called Dean just because it was easier that way. (so he told himself.) After he'd rebelled, keeping track of Dean became much more important to him. Because Dean was his friend. (friend, friend, he repeated to himself, so much it became almost a prayer.)

Never mind how green his eyes were. Never mind he was one of the bravest people he'd ever met. Never mind that it did uncomfortable things to his heart (and pants) when Dean stared at him without blinking. (there was a reason he always invaded his personal space.)

When Dean killed the Whore, Cas realized what he was contemplating. Whatever remaining hope he'd had in Dean vanished. Rage swirled in him like a storm, and that human emotion opened all the doors he'd kept so tightly locked. Now when he looked at Dean, he felt rage and disappointment and yes, lust and lots of it. Standing in front of Bobby's panic room, it was written all over his face.

"Not for nothing Cas, but the last time someone looked at me like that I got laid." Cas had been a little shocked, and when Sam had asked for a minute, Cas had slammed the door shut and fallen against the wall, shaking at the flood of feelings. When Dean had banished him, he'd felt even more betrayed. Hurt and enraged beyond belief, Cas found him about to turn himself in to the angels. He dragged him into a dark alley and unleashed his superhuman strength on Dean, heedless of his pleas until he saw Dean's face bleeding and those green eyes desperate that he gave in and brought him the unconsciousness he needed. And for a moment he stood there and stared at him, trying to understand how one human could bring him such turmoil.

Cas truly meant it when he said he did not want to watch Dean fail. He couldn't stand to see Michael invade the man he (so badly desired) considered his closest friend. Banishing himself was the only way to escape the emotions.

When he woke in the hospital, he dialed Dean, his heart racing. The relief he felt when he realized Dean was still Dean was so strong he felt dizzy(er).

After he got Pestilence's ring, his heart sank when he realized Dean was going after Death alone. He couldn't bear to leave without saying goodbye.

"Dean."

"Cas."

"Don't die."

Dean's lips quirked a little and before he could help it, Cas leaned forward and pressed his lips to Dean's. He backed away as soon as he'd realized what he'd done. Dean just stared at Cas, and Cas stared back. Then, so quickly it stunned even Cas, Dean was pressed against him, pinning him against the wall with his whole body. Cas felt a warm flush spread over his body as Dean placed his hands on the wall on either side of Cas's head and leaned in. His lips paused less than an inch above Cas's.

"Now why would I do something like that, when I've got so much to live for?" Cas was smiling when Dean kissed him.

Twenty minutes later, Sam and Bobby glanced up to see Dean's hair sticking up straight and Cas's tie even more lopsided than usual. Bobby cocked an eyebrow at Sam, who just shook his head, deciding it was better if he didn't ask. Neither of them missed the significance of the look that passed between Dean and Cas as Dean got into the Impala. As he drove away, Sam turned to Cas and grinned. Cas cocked his head at him, then smiled back hesitantly.

At least now he had a reason as to why Dean was number one.