"Muro-chin."
Himuro knows he shouldn't look up. He knows that tone in Murasakibara's demanding drawl, knows that if he reacts he will be as good as submitting before he even knows what the request is. If he keeps his head down and doesn't make eye contact, it's possible that Murasakibara will drop whatever request he has as too difficult to pursue, as not worth the effort of pushing for attention, and Himuro won't find himself giving in as inevitably as he always does.
He looks up anyway.
"Give me that," Murasakibara says as soon as he sees Himuro looking at him, reaching out for the just-started box of pocky the other has leaning against his knee. His tone is peremptory, certain in Himuro's compliance as he reaches for the snack, until it's only the speed of the other's motion that saves the box from the crushing possession of Murasakibara's fingers.
"They're mine," Himuro protests, holding the box close against his chest as Murasakibara moves to sit up, the boredom over his features clouding into the threat of stormy irritation, the outline of frustration forming into lines at his forehead. "You had two boxes of your own already."
"Mine are gone," Murasakibara says, a simple statement of fact without any admission of responsibility for the current situation. It's as if he's saying the sun is up, observing a natural phenomenon rather than acknowledging his own complicitness in the situation. He reaches out to curl his fingers around the box under Himuro's determined hold. "I want more."
"I want some too," Himuro complains, clinging to the box even against the deceptively casual tug of Murasakibara's hand around it. "You ate all the rest."
"It's my birthday," Murasakibara says with the slow satisfaction of one who knows he's just offered an unassailable point. "You have to be nice to me today."
"Atsushi," Himuro sighs. "You've been saying that all day."
"It's still true." Murasakibara gets his fingers in the top of the box and fishes a stick free. He eats it in two bites, so fast Himuro isn't even sure he's tasting it, licks the traces of crumbs off his fingers before reaching for another.
Himuro interposes his hand between Murasakibara's fingers and the box, cutting off the attempted attack before it has settled. "Not like this," he says, pushing Murasakibara's grasping fingers away so he can pull a stick out himself.
"Muro-chin-" Murasakibara whines, protest forming itself to resonance in the back of his throat.
"I didn't say no," Himuro says, turning the stick around so he can lift the pale end to his mouth. "You can still have it like this. You only really want the chocolate anyway, right?"
Murasakibara watches Himuro brace the pocky against his lips, watches him catch the end between his teeth hard enough to hold it steady but gently enough that he won't bite through. His eyes are dark, steady and considering.
"I didn't want to share," he says, a last pout of irritation, and then he's leaning in, faster than Himuro was truly expecting him to. He takes the pocky in two quick bites, one right after the other, the second so close his teeth skim the edge of Himuro's lips as he bites through the stick. Himuro sucks in a startled breath through his nose, a shocked rush of air at the heat of Murasakibara's mouth so close to his as the other boy chews, swallows, doesn't pull away.
"You're selfish, Muro-chin," Murasakibara rumbles, and Himuro catches what is left of the pocky on his tongue, tries to remember how to eat without choking while Murasakibara is so close and breathing so hot over his mouth. "It's my birthday, you know."
Himuro swallows fast, reaches for words that come out shaky and laced with anticipation. "Yeah," he says, reaching up to ghost his fingers over Murasakibara's hair, to lace them into a hold light enough that the other boy doesn't protest. "Happy birthday, Atsushi."
Murasakibara tastes like chocolate when he licks into Himuro's mouth, the taste sweet and heavy against his tongue. It's better than the pocky would have been anyway.