Iwaizumi doesn't hear Oikawa calling for him.
He left the other asleep in bed almost an hour ago, wrapped up so tightly in the blankets he had stolen from the other side of the bed that even Iwaizumi's early-morning grumpiness couldn't persuade him to wake Oikawa by dragging them back. He got up instead, luxuriated in a shower absent either Oikawa's persistent demands that he finish or the very different distraction of the other pressed warm and wet and purring against his spine, and by the time he makes his way out to the kitchen in pajama pants and a t-shirt he's feeling languid with comfort and ready to tolerate whatever whining Oikawa will give him when he finally gets himself out of bed. He's waiting longer than he expects - usually Oikawa can't be left alone for more than fifteen minutes before he comes whimpering for attention - and then he doesn't hear the other's voice, doesn't hear anything until there's the sound of feet shuffling down the hallway.
"Iwa-chan," comes a voice. The nickname is familiar, the sing-songy lilt of the syllables years in the making, but the sound is grating instead of sugar-sweet, the high notes catching into silence while the lows drag raw over exhausted vocal chords.
Iwaizumi looks up from the tea he's waiting on to give Oikawa a long stare. The other is standing at the edge of the kitchen, wrapped in the blanket he stole from Iwaizumi this morning and with his hair tangled into a true mess instead of the artful impression of one he usually cultivates. His nose is red, his eyes bleary, and when he repeats "Iwa-chan" the tone that is meant to sound plaintive cracks into something croaking and pained.
Iwaizumi looks at Oikawa for a long moment before he turns back at the teapot in front of him. "Who the hell are you?"
"Mean," Oikawa protests, sounding completely and thoroughly miserable and nothing at all like his usual irritating self. "You're a mean person, Iwa-chan."
"You sound like a frog." Iwaizumi says as he turns towards the cupboard and reaches up for a cup without looking at Oikawa's woebegone expression. "Or a grandfather."
"I'm sick," Oikawa says, as if this weren't perfectly obvious. Iwaizumi reaches into the cupboard, retrieves a slightly sticky bottle of honey while Oikawa shuffles in to press his forehead against the other's shoulders. "You're supposed to take care of me, not make fun of me."
"This is what you get for staying up all night," Iwaizumi informs him. Oikawa clings to him when he tries to turn back to the pot of tea; it makes moving slightly harder, requires a dig of his elbow in against Oikawa's chest before he loosens his hold enough for Iwaizumi to move. "I told you you'd make yourself sick, you should have listened to me."
"I will next time," Oikawa lies, sniffling himself back into a too-heavy lean against Iwaizumi's back. "I need you to nurse me back to health, Iwa-chan."
"Go back to bed," Iwaizumi insists without a trace of mercy in his voice, spooning the honey out of the bottle and into a golden glow at the bottom of the cup. "Nurse yourself, I don't want to catch your cold."
"Iwa-chan," Oikawa whines, and his voice might sound like a stranger's but Iwaizumi would recognize the irritating insistence in that tone anywhere. "Why are you always so mean to me?"
"Because you deserve it." The tea splashes over the honey, knocks droplets of sweet loose into the liquid as it spills into the cup. "Let go of me."
Oikawa whimpers something tragic and incoherent against Iwaizumi's shoulders. "I don't want to."
Iwaizumi sets the teapot down and reaches out to close his fingers on Oikawa's wrist. It takes some effort to pry the other's hold loose, but Iwaizumi has the advantage both of size and health, and whatever contest might have existed is decided well before he manages to work himself to freedom so he can turn around and glare at Oikawa.
"Don't be a baby," Iwaizumi suggests, and lets Oikawa's wrist go so he can brace his hands against the other's face instead, can hold him still so that when he leans in to bump his forehead against the feverish heat of Oikawa's the other can't make an attempt at a kiss. "You should be in bed instead of wandering around the house."
"Give me a kiss to make it better," Oikawa suggests, trying to turn his chin up for the contact in spite of Iwaizumi's hold on him.
"No way." Iwaizumi pulls back, pushes Oikawa away in the vague direction of the bedroom. "I'm not going to get your cold because you were too stupid to go to bed when you should have." He turns back to the counter to pick up the cup of tea, pivots to push it against Oikawa's chest as the other starts to approach again. "Drink this, it'll help your throat."
Oikawa looks down, blinking at the cup like he doesn't completely understand the statement. It's a moment before he lifts his hands to take the weight of the cup from Iwaizumi's fingers, another before Iwaizumi trusts his hold enough to let it go.
"You made this for me?" he asks, ducking his head to breathe in the honey-sweet steam. "Iwa-chan, you are a good nurse after all."
"Shut up," Iwaizumi orders. "Talking isn't going to make your throat any better."
When Oikawa looks back up, his eyes have some hint of their usual sparkle to them. The smile he offers is slow, more of a fight than it usually is, but Iwaizumi can see the sincerity in the curve of the other's lips.
"You miss my beautiful voice, huh, Iwa-chan?"
"Shut up," Iwaizumi tells him, and leans in to enforce obedience with a kiss after all.