Synopsis: In the show, Sam doesn't swear. Even when reading an article to Dean he pauses and hesitates on what to do when he comes upon the b word, letting Dean fill in the blank before he continues reading. Why? This is a moment between 12 yr. old Sam and 16 yr. old Dean explaining why, but it starts with them as adults, around S13 or so.

Present Day

"So what's the deal?"

Sam starts reading from his laptop while Dean drives. "It says here that there have been three deaths, each on a full moon, and all of the bodies were left behind a bar called…," and that's where Sam freezes, unsure what to say.

Dean peaks over, "Bitchin' Moonlight."

Then Sam continues summarizing, as though he'd never paused.

A few decades earlier…

Dean watched Sam's hand slide up and down the backpack strap. Again. The kid had been fidgety since Dean had met up with him outside Sammy's school.

Dean knew his brother. He'd raised him. The kid had either gotten himself in trouble and was working up the courage to confess or he was trying to work up the courage to cause some trouble.

Sam twitched again. Dean decided to let him keep working on that build up of courage. He'd give him exactly eight more minutes before he forced a confession out of his brother.

They got back to the rental of the week and geek boy immediately started digging through his backpack, but with those odd twitchy movements, a change to his breathing, and a slight blush. They really needed to work on Sam's deception skills. Dean knew that whatever Sam had been building up to, was about to be spit out.

Then it happened.

"Son of a bi-"

"Don't you dare."

The harsh reprimand had Sam freezing, with the barest hint of the b on his lips. Then his face flushed scarlet and Dean knew. That's what the twitchiness had been about. Little bro was testing to see if big bro would allow him this tween right of passage. Not going to happen. Ever.

"Park it." Dean pointed to a chair.

Sam sat and stared at his hands, wringing them. What was the big deal? Dean had been swearing for years, out of earshot of Dad or any other adult. But that's the way it's supposed to be. You hit 12 or so and your vulgar vocabulary is allowed to expand around your peers.

But there in lay the problem and why Sam had been nervous about trying out the b word. Sometimes Dean was his peer and sometimes Dean was his parent and Sam hadn't been sure which role Dean would decide to play. It was a risk, but a boundary that it had come time to test. Sam nibbled his lip, unsure if he liked Dean picking the parent role on this one.

Dean took a seat in front of him. "Eyes up, Sammy."

Sam fidgeted, then straightened up, shoulders back because Dean had taught him that when you screw up you accept what's coming to you and when you want to talk something out with someone you buck up the courage to look them in the eye while you talk.

"Sam, I know you believe you're old enough to swear and I've been a pretty shit example. But this isn't about age."

"Sure seems like it. Why's it matter, Dean? You and Dad have me practicing lock picking, the art of car theft and proper techniques for digging up and burning corpses. Why does it matter if I swear?"

"That's precisely why it matters."

"Huh?"

"Childhood, innocence, those things pretty much died for me the night Mom died. But I've always done the best I could to give them to you. You let that kind of language slip out, it strips away a layer of that innocence. You're someone different afterwards, even if it's just a smidge more mature."

"I can't stay a kid forever, Dean."

"I'm not asking you to."

"Then what are you asking?"

"I'm asking that you keep a part of you innocent, for the both of us." Dean held out his hand with the pinky finger up and crooked, in the gesture or childhood promises, "I want you to swear that nothing worse than the word jerk ever passes your lips."

Sam hesitated, knowing that if he hooked his pinky with his brother's and swore, he'd have to keep that promise and deny himself this right of passage.

Sam's eyes held on the charm he'd gifted Dean, the one that symbolized that Sam understood that Dean was a pseudo parent to him, and of his two parents, Dean was the one he could fully trust. Dean had given up his own childhood to take care of him. He could give up this one right of passage for Dean.

Sam reached out his pinky and hooked it with Dean's, "I swear, no swear words."

Dean smiled with relief, then ruffled Sam's hair, "Bitch."

Sam smiled and shoved his hand off, "Jerk."

Present Day

Dean no longer wore the pendant, abandoned it years ago, on a night best forgotten. But the promise Sam made, that he swore to keep, he'd kept. And Dean felt good about that.

The End.