It started, like so depressingly many things in the Winchesters' lives, with a lie.
Sam was seven at the time, only an elementary schooler but old enough to feel himself not fitting in. Old enough to feel other, to feel in his constant switching between schools like someone walking on the sidewalk, peering through the glass of homes he'd never enter. Always on the outside.
Making friends was hard when he had so little time and so little in common with his peers. Eventually, the strange looks and uncomprehending pauses prefacing incredulous questions (you don't have a house? you've been to five other schools? you don't have a mom?) started to wear on him, and Sam learned a lesson his father had already been well on his way to teaching him: lying is easy and quick and it smooths over so many of life's little hitches.
So his standard replies shifted away from Yeah, no house, yeah, I keep moving around to different schools, yeah, my mom's dead to of course I have a house, this is my second school, of course i have a mom. At first, his lies hesitate and stutter, and elementary schoolers aren't really a suspicious bunch, but the gentle follow-up questions of teachers and other parents is enough incentive to propel Sam down the road to expertise. By his eight-and-half-th birthday, Sam can lie as fluidly as a conman, with a smile on his face and wide, innocent eyes.
Lying about having a house is easy: all Sam does is remember back to a house they stayed in once. It was long enough ago that the memory is fading, but his friends only really need the broad strokes. He describes his house the same way, over and over again: yellow sides, brown door, and a big window in the front with three panes that jut outward, meaning the sill inside is more like a bench, a perfect place to sit and watch the outside world.
As far as talking about previous schools, he only ever mentions the last one he went to, lets everyone around him assume that that's the only other place he's ever lived. Those lies become so familiar that Sam sometimes imagines the kid who lives them really exists, somewhere in his head.
But the third one, his mother, is harder to get right. Sam can't remember ever having a mother, and when he assumes that she'd act basically the same as his dad, those sideways glances start right back up again. Okay, so moms don't leave in the middle of the night sometimes and come back a strange kind of happy. Okay, so moms don't disappear for a few weeks to take care of work. Okay, those are dad things. So what are mom things?
Sam figures it out all at once one day, when an almost-friend of his is talking about how his mom took his to the new ice cream shop in town even though his dad didn't want her to. When it's his turn to share a story, he almost forgets all those lessons he's learned about lying, tongue tripping over itself the euphoria of understanding. Finally, finally he gets it: mom things aren't dad things, mom things are Dean things.
So Sam tells a story about how his mom once accidentally packed him a sandwich with moldy bread for lunch (Dean hadn't believed him at first, hadn't believed that Sam knew what mold looked like until he checked the rest of the loaf and found the bluish white fuzz growing underneath it. The look on his face when he realized he'd have to figure out something else for dinner isn't something Sam wants to think about, isn't the funny part of the story), and when everyone laughs at his exaggerated claims of how bad it smelled, Sam feels the comfort of belonging in a way he never has before.
And that's how it goes, in the following months, new school after new school but always the same lies, on and on until the lines in Sam's head start to get kind of blurry. After a certain point, "Mom" is just another name for Dean.
So things go more smoothly at school, and just the same amount of roughly at home, until Sam slips up, one night.
It's late. Not actually Sam's bed time, not yet, but he's on the tail-end of a nasty fever and his body's still a little worn out, so while Dean sits against the headboard, Sam dozes with the top of his head against his brother's hip and Dean's hand tangled in his hair.
He sinks into dreams for a minute, then drags right back out of them with an achy kind of feeling in his chest, limbs and heart heavy like he's been running away from something terrible. He squirms a little, waking up, and Dean pulls his hand away.
Sam makes a noise a of protest that goes entirely ignored, possibly because Dean, with his ears already strained toward the near-silent TV, didn't hear him. Sam sighs. Dean is too far away, sitting up like that. Sam knows it isn't really time yet, but his head kinda hurts and he doesn't wanna have any more of those barely-remembered dreams that were definitely closer to nightmares.
"Mom," Sam says, into the fabric of Dean's pant leg, "can you come lay down?"
Dean turns to stare at him, brow furrowed, and it takes Sam a second to realize what he said. "Sorry!" he squeaks, mortified. "Sorry, Dean, I didn't mean to--um--"
"...it's okay, Sam," Dean says after a minute. He turns off the TV, after a second's consideration, and then, to Sam's surprise, he lifts the covers and scoots down in the bed. His arms wrap around Sam, and Sam's body settles against his automatically, knowing exactly where they're meant to line up. Dean lets Sam pillow his head on his chest, like he's not even going to mention Sam's weird slip-up, like it really is okay.
But it's not okay, suddenly. Suddenly, Sam is swimming in guilt for all those lies he's been telling, and suddenly he needs Dean to tell him whether it's okay, whether it's forgivable, to lie so much for such a stupid reason. For a few minutes, Sam listens to his brother's heartbeat without slipping an inch closer to sleep. Then he takes a deep breath and suddenly the whole story pours out of him, everything, all laid out into his brother's soft sleep-shirt for judgment.
Dean is silent for a minute, after Sam finally gets it all out. Nervous, Sam lays completely still (he hates when Dean is mad at him, hates it even more than when Dad is mad at him, because Dad is angry all the time but when Dean's mad Sam know he's right to be) half on top of his brother and terrified that if he moves, Dean won't let him back this close ever again.
"It's okay, Sammy," Dean repeats after a minute. Sam blows out a breath, melting in relief. "It's okay. You, um--you can keep calling me that, if you want. I think it's not...it's not fair that you don't have a mom. You deserve one. And I guess I...I try. To be like her. To give you that. So...it's fine. Whenever you want to call me that, it's fine."
Oh. Thatβ¦isnβt exactly the kind of answer Sam is looking for. Itβs not really the question he meant to ask. But if Dean's offering...
He turns, hesitantly, pushing himself up on his elbows to look Dean in the face. "...Mom?"
Dean clears his throat. "Um, yeah? Yeah, Sammy?"
Sam blinks away unexpected wetness in his eyes. "Mom. Thanks."
Dean smiles at him, and it's all soft and happy. Sam lays his head back down as Dean whispers, "No problem, Sammy," and cards a gentle hand through his hair.
βMom,β Sam breathes again. As Sam sinks into a deep, safe kind of sleep, it settles between them, a new, private kind of truth.