The first time Dean does it it’s with a huff. He smacks Cas’ hand away, undoes the mess of a knot that’s already there and then expertly ties the two ends of the blue strip into a perfect Four in Hand.
The second, third and fourth time he does it, it’s much of the same but by the fifth time he notices Cas’ brilliant blues trained on his face. Then, he starts noticing just how wide Cas’ shoulders are. He’s a slender guy, more lean than bulk, so Dean is just surprised by the width there . The strength of the body with or without angelic grace.
Somewhere around the tenth time, Dean starts letting his knuckles drag against the stupid dress shirt he never sees Cas without. There’s a warmth just underneath it and Dean doesn’t think about skin on skin, he doesn’t think about taking off Cas’ tie instead of tying it for him.
Eventually the tie stops being a solid blue colour and is replaced by one that has stripes. Cas comes to Dean and cranes his neck back without taking his eyes off of him, just like usual. Dean keeps up with the mock-annoyance and pretends that these moments aren’t the best part of his day even though he stands closer now, takes longer than Cas knows he needs.
Things change one day, Cas’ eyes leave Dean’s to focus on his hands instead. Cas says, “One of these times you’ll have to teach me. Seems more efficient that way.”
Dean has never tied a tie so fast in his life.
Cas keeps it up the next few times, tries to figure out the movements so he can recreate them himself. Once, Dean walks in on Cas, tongue caught between his lips, standing in front of Sam’s computer watching a How To on Youtube.
He grunts and shuts the laptop lid. “You’re taking too long,” he barks out, startling Cas. “We need to get going. Just let me do it.”
It takes a dozen more times for Cas to ask, “Why don’t you want me to learn?”
Dean doesn’t answer, just finishes his half Windsor (he’s been switching it up to confuse Cas because Dean is mature) and leaves.
The next day Cas starts, “Dean, why-”
“Why do you even want to learn, Cas?” Dean snaps back agitatedly, tugging at the strip a little too forcefully. “I’m always around, aren’t I?”
“I’d like to,” Cas pauses, hesitates. “Return the favour.”