Ever since his father first brought your newborn self into the pack, offering no explanations as to where you came from and simply claiming that you were blood-related to them, Sam and Dean have been all over you. Dean had already presented as an omega when you were first introduced, so he was the one who spent the most time taking care of the scenting at first—considering that their father didn't even bother doing that for his two sons, let alone his newborn—followed by Sam a couple years later, once the younger Winchester finally presented as an alpha, before he left for Stanford.

But once he reunited with his brother and little sibling? His heart was torn. You'd still happily let Sam scent you, clearly content with having a member of the pack return, but he'd taken notice as to how quiet you were compared to normal pups. You could imitate something akin to a hiss or a shriek when presented with danger, which could alert Sam and Dean in case you needed help, but other than that you just... didn't make a single sound. You only made sounds when in distress, and that—well, that distresses him.

He tried asking Dean about it, wondering if you had ever even purred, which earned him a very weird eyebrow raise and a 'Have you ever heard me purr? There's your answer.' Which made sense, but it stressed the alpha out regardless. Not teaching pups the different positive sounds and something as basic as purring can be very damaging; you'd be stuck trying to guess social cues and maybe find yourself in unwanted situations or get misunderstood, Sam didn’t want that for his baby sibling. But how could he teach you how to purr if he never learned himself? He's only ever heard Jess do it, and he had already presented by then so he couldn't exactly mimic the sound as gracefully as she used to do it.

He managed to rope Dean into teaching you some positive sounds, and he was so happy to hear you trill and occasionally chirp whenever he chuffs at you (even if you overuse it sometimes, but it's nice to hear nonetheless), but purring is something he'll have to teach you... somehow. Sam hasn't exactly figured out a strategy yet, but he's determined to at least try for you.

"Pup?" Sam calls when he enters the hotel room, seeing your little form sprint towards him, "Hey there, miss me?" A chuckle escapes him, as he unconsciously starts crooning to soothe your overzealous behaviour, and to his surprise you try to mimic it—maybe this could be a start into trying to get you to purr when you're content. "Try that again, pup, you almost had it... maybe add a bit of a rumble to it?"