Seto's arms are warm.
Seto himself is warm, like a human furnace, like the embodiment of sunshine, with all his kind words and radiant smiles (and Kano hates how poetic he sounds but it really can't be helped). He's a comfort in the midst of a cold night. He smells good too, Kano notes, smells of the woods he likes so much and the musty air of the apartment and something so remarkably Seto and Kano can't help but melt into the embrace.
He's crying though, much to his dismay, wetting the recently-washed jumpsuit with his pathetic tears and he hopes Seto won't mind- knows he won't mind when one of the arms wrapped around his shoulders draws up to the back of his head, pulling him gently closer against his chest. He doesn't say anything- neither of them do; Kano's thankful he doesn't have to risk responding to anything with the way his voice would crack because dammit, he still hasn't stopped crying.
But Seto is warm, blocking out the chill wind blowing in and the dark world around them. Kano is clutching at his clothing, trying- trying- to steady himself, to put a stop to this out-of-place scene. But it's not working and Seto is warm and he really wants to walk until his feet ache or maybe lie down for a few years.
Seto is warm later too, sprawled out on his bed with him (Kido hadn't said anything when they'd shuffled through the door, Seto's arm still draped over his shoulder and Kano's hood pulled low over his face, merely given them a sidelong glance and let them continue on without a word), wrapping him in a cocoon of limbs and blankets so sweltering he thinks he might suffocate. But Seto is holding him like he's the most important thing in the world- the thought alone almost makes Kano want to cry again- and he doesn't have the strength or the will to get up.
Yes, Seto is warm while Kano is cold. But at least for these few precious moments, Kano is able to share some of that warmth with him.