Some samdean agere headcanons…
Sam never grew out of sucking his thumb as a kid. After their dad’s increasingly angered attempts, Dean bargained it was fine if Sam only did it when their dad couldn’t see. Sometimes it’s the only way he can get to sleep.
So much hand holding/ sleeve holding/ jean-back-pocket holding- the works, anything that boy can hold on to he will. A rip in Dean’s jeans? You know Sam’s fingers will find a way in there. When chatting with Garth or Jody about a case outside, Dean’ll hold Sam’s hand tight so he can’t wander off, bored and wanting to go explore.
Lap sitting- especially bunker era, Dean sitting at the war table and Sam coming in, sitting down on his lap and Dean’s conversation with Cas not wavering for a second, maybe a hand up the back of Sam’s shirt or a bouncing knee to give Sam the contact he’s looking for.
He has a Blankie. A soft scrap of fabric Sam sleeps with, sometimes carried around the bunker when he’s feeling especially sensitive- stuffed into old gym bags or duffel bags or backpacks when travelling.
Uses gear very rarely, may need a dedicated weekend-off for Sam to accept a pacifier, kid cutlery or a bottle from Dean.
Super sleepy regressor- Dean makes sure to put him down for a nap every time and takes him back to bed when he inevitably wakes and goes searching for him, snivelling and soft-footed.
He’s incredibly shy and quiet and often becomes nonverbal if it’s not just him and Dean around when in his headspace. He’s very quick to cry.
Super tactile, as mentioned prior, always wants to be touching/ fiddling anything regarding Dean- his ring, hands, shirt buttons- may sit on his hands when interviewing witnesses or with friends to stop himself.
Loves face tracing and hair brushing, Dean tracing the bridge and point of his nose, his cheekbones, his brow, or sitting him down between his knees in the morning to brush out his bedhead.
Dean wears a couple beaded bracelets around his wrists, cheap and colourful beads on thin elastic, that Sam made for him.
Dean notices one day when Cas comes over to discuss ingredients for a spell, the angel has one around his wrist now too.
Charlie would be one of their only friends who know (aside from Cas, nosy bastard), sussing it out instantly and smirking to herself whenever she notices one of Sam’s tells. She might also turn up with a bracelet or two.
Rowena would definitely get a bracelet, which would result in Sam getting a gemstone one in return, sprinkled with some protection magic.
Around s12, Mary is dumbfounded by her sons’ close bond, wondering why her 34 year old is tugging the sleeve of her eldest for attention. She’s even more dumbfounded by the lack of reaction it gets from everyone else. After a brief conversation regarding Dean’s dating history (which felt like getting blood out of a stone), she assumed the bracelets on his wrists were from Ben, and decided to leave that sore subject alone.
Dean loves calling him Sammy-girl or Sammy-boy, alongside Princess, Sweetheart, Kiddo, Baby brother, Little brother and Baby boy. He’s got a million, including a fuck-ton of niche movie references, but those he frequents most.
Sam calls him De, or De-De when excited, very rarely calling him Daddy/Papa. Dean very much enjoys when that happens, albeit infrequent.