Author's Note: Bad news: I'm sick. Good news: it inspired me to write this little bundle of nonsense. Enjoy!

Oops

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Aunt Cass slaps her knee and doubles over, cackling.

She calls him a harlot loud enough for the café regulars to hear when Baymax gives her the diagnosis, and clutches her aching stomach. The med-bot, with an endearing blink, calmly explains to Hiro what the illness means, treating him more like an adult instead of the brash fourteen year old he is.

Mononucleosis. The Kissing Disease.

He could have contracted it from anywhere, Baymax states. Drinking from someone's glass. Sharing lip balm. The likes. But Hiro knows exactly where this originates.

Honey Lemon.

If he didn't like her so much he just might've killed her.

As Baymax lists of a full prescription of a day's rest and an appropriate set of balanced meals, Tadashi bids Hiro goodbye with an imperceptible smirk. The younger grumbles face-first into his pillow, swathed in a mountain of blankets to wallow in his achy muscles and cold sweats, whilst his aunt is fighting a losing battle to cage in her amusement. She snorts into her hand as she brings him soup, tears leaking from her eyes.

"My nephew, a ladies man," she cackles, struggling not to drop the tray. "Oh, and everyone thought I'd see the worst with Tadashi! The girls at beat poetry owe me ten bucks each."

She assumes—correctly so on a technicality, but that's beside the point—that Hiro got this the old-fashioned way. While he's a little hurt not to be given the benefit of the doubt, he isn't surprised. With an aunt like Cass, the most outrageous theory must always be the truth. So he listens to her ravings and bears the humiliation in silence, yearning wistfully for times when he remembered what it was like to be happy.

Four hours later, long into his mourning period and longer before it'll end, Hiro reaches for his cell phone to call the one person who listens when he whines.

"'Dashiii," he moans when his brother picks up. "'Dashi, it hurts."

"What does, Hiro?" the older boy, as usual, takes it in stride. Hiro doesn't want to hear it. He wants sympathy. And cuddles. And gummy bears. Another blanket. Or two. Because when did it get so cold? It's, like, t-shirt weather.

"Everything," he slurs, smooshing his face into the pillow and curling into a tight ball. "Come home. I need you, 'Dashi. Make me tea, hug me, and warm me up, 'cause it's so cold, and when did it get so cold, 'Dashiii?"

Really, there's no question about it.

Resisting is futile, because Tadashi simply can't when Hiro is like this. Vulnerable and sad and, honestly, a little pathetic. It's so rare that Hiro is reduced to showing this side of himself, and Tadashi restrains from dashing home right this minute, to wrap his otōto up in his arms and dispel the pain through undying affection.

He makes a pit stop on his way home to collect two family packs of gummy bears, notoriously the only cuisine Hiro can stomach amidst a fever, and gives his aunt a quick hug before ascending the stairs.

Nobody can say Baymax isn't well-designed. His creation stands on the landing, a squishy but sturdy roadblock between the two brothers.

"Mononucleosis, while non-fatal, is highly contagious," the med-bot advises. "I highly discourage close contact with the infected individual."

He's about to protest to the best of his ability, when a muffled thump from behind Baymax cuts him off.

"Hiro." Baymax's head rotates towards the addressed. A pause. "You have fallen."

"Huuurts," comes the plea.

"I will scan you now." One second later, "Scan complete. I detect no injuries, however please exercise caution—a fall from even a small height can lead to bodily harm." He tilts his head. "Your neurotransmitters are low, Hiro. This indicates that you are unhappy."

As if he'd be capable of wringing sympathy points from a robot, Hiro whines against the floorboards. And while the sound pits Tadashi in the zone between heart wrenching pity and wanting to slap his forehead hard enough to bruise, his hand freezes midway when—dare he say it—Baymax hesitates.

He can practically hear the clogs whirring in the robot's head. He's considering it.

"Emotional stability can greatly improve chances of a full recovery." Another pause. Then Baymax sounds akin to resigned as he asks, "Would spending time with Tadashi improve your emotional health?"

All flushed skin and glassy eyes, Hiro bobs his head. If there was any doubt in the earlier deduction, Baymax dashes it as he shuffles aside.

"Please be cautious," the med-bot warns, "Mononucleosis is highly contagious, and can be easily transferred via direct or indirect oral contact."

Tadashi hears none of it, darting around his creation to zone upon his little brother, who lies sprawled across the floor literally crying for his nii-san. On the sidelines, Baymax silently observes as Hiro is scooped up and tucked in so snugly he can do little more than squirm and whine when Tadashi leaves his line of sight.

By the time Tadashi returns with a thermos of herbal tea and an extra blanket, Hiro's arm is free and promptly latches to Tadashi's shirt like Velcro once he's within range, looking up at his brother with desperate eyes.

"Nii-tan," Hiro heaves, half-drunk with fever. "Tada-niii, you were gone so loong."

And all of a sudden, Hiro is six years old again, experiencing his first miserable bout of the common cold. Stuffed-up, croaky-voiced, and suffering. He'd clung to Tadashi then, too, meekly kicking aside Aunt Cass the rare times she braved her outspoken squickiness against contagious children with mucus dribbling from their noses to deliver soup and heartfelt wishes.

Old habits die hard, it appeared.

"I know, otōto," Tadashi soothes, heaving the nearest quilt over the younger's skinny shoulders. If Hiro won't lie down and sleep like he should, then Tadashi can at least keep him appropriately toasty. "But it's alright now. Nii-chan's here."

It worked a charm eight years ago, and doesn't fail now.

Delirious and clingy Hiro may be, he is reassured into obedience. He doesn't protest as Tadashi buries him in blankets, coos happily as a damp towel is pressed to his forehead, and (begrudgingly) slurps down the icky soup Aunt Cass whips up for lunch.

("Family recipe! Soothes the throat and settles the stomach. You'll be back in the shower singing opera in no time," she'd promised, cheerfully unaffected by the weight of Hiro's death glare.)

Tadashi wishes Hiro were always so easily pleased: he whimpers at a chill, an extra blanket sorts that out. He pines for attention, a hug calms him down. He wants something, he asks.

It's refreshing to discard the guessing game entirely and just flip over the answer cards.

His most recent complaint is the slow burn reforming in his throat.

Tadashi lifts the rim of the cup to Hiro's slack lips, carefully guiding him to drink the warm tea. Hiro moans as the herbal blend soothes his aching throat, and applies conscious effort to keep a majority of it dribbling down his shirt. With mixed results.

Baymax then recommends a dry change of clothes and Tadashi rearranges Hiro's limp arms into a new shirt. (It doesn't surprise him when Hiro insists on using one of Tadashi's—some habits stand the test of time, despite neglect.)

It might have been a poor move.

In the most lucidity he's been in all day, Hiro then insists he's healthy enough to curl up on the battered couch and help Tadashi tinker in the garage (a.k.a. replace Baymax's lollipop supply with a dispenser of gummy bears) but his pleas fall on deaf ears.

He quiets down as Tadashi crackles open the actual gummy bears, too preoccupied with suckling his way through half the pack one bear at a time as Tadashi tenderly rubs his back and Baymax keeps a sharp attentiveness towards any non-existent signs of a choking hazard.

A peaceful hour trickles by, disrupted periodically only as Baymax restocks the thermos of tea with recommendations of keeping up Hiro's fluids, and Tadashi is content to spend the remainder of the day tracing idle patterns into his brother's back.

Hiro, on he other hand, isn't.

"Nii-san? I'm still cold. C'n you get under the blankets, too?"

Tadashi, the epitome of perfect health, really couldn't reach any level of comfort under a mountain of three quilts on a warm day, but he holds back a sigh as he obliges. Not because Hiro would do the same for him (because the demonic spawn lacks all empathy) but because he's a masochist who can't say no to someone in need.

His movements sluggish, Hiro curls himself around every available inch of his brother, arms in a vice grip around his waist and head tucked below Tadashi's chin.

"Better?" Tadashi inquires, giving Hiro a squeeze. His nose twitches as Hiro nods, inadvertently tickling him with fluffy black hair.

"You're the best, nii-tan," Hiro burbles. His body is clammy and his words melt on his tongue, fever showing zero signs of respite, but he's comfortable now that he ceases his incessant wriggling.

"Sleeping is often an excellent remedy to speed up the healing process," Baymax interjects, one finger held high. "Might I suggest taking a nap?"

Hiro groans against Tadashi's collarbone. It reminds the latter of a disgruntled Mochi that month he was put on a diet.

"You're not doing yourself a favour by staying up." He runs his hand through Hiro's scruffy bird's nest of hair. "You'll feel better for it, I promise. I'll be right here when you wake up."

"Yeah?" Hiro lolls his head back like it weighs a ton, and squints at Tadashi. "Pinky swear?"

He smoothes down a wayward lock from Hiro's damp forehead. "Absolutely."

The sickly boy smiles lazily, too disoriented to set the vow in stone, and cuddles closer, as if he could burrow right into Tadashi's warmth. "'Dashi?" he murmurs, happily as can be. "Love you, sooo much. You're, like, the best nii-san I'll ever have, ever."

And so what if he wants to be a little mushy at times? It's his opening to be honest without Hiro scoffing (and blushing).

"I'd never trade you for the world, otōto." Even if you do drive me crazy.

"Dashiii?"

"Yes?"

Hiro shuffles inside his blanket cocoon, an awkward maneuver that inadvertently involves a lot of grabbing, tugging, and sharp elbows digging into Tadashi's stomach. Until eventually, Hiro has his cheek pressed to his brother's collarbone, hot breath ghosting over his exposed neck.

"Comfortable?"

In another spot-on Mochi impression, Hiro nuzzles his face along Tadashi's jawline, purring contently along the way. And with the irregular squeaks of Baymax tending to the laundry in the background, Hiro traces his nose along his brother's cheek and with impeccable coordination skills, closes the gap between them to latch his mouth to Tadashi's.

He wouldn't call it a pleasant kiss; it's a hot, sloppy, very wet smooch that smothers Tadashi's lips for a bewildering five seconds.

Tadashi is the one who breaks it, cupping Hiro's cheeks and prizing the little leech away with a generous smack of their lips. Hiro flashes him a goofy, gap-toothed smile, lips glistening with strawberry-flavoured saliva until he smooshes his face into Tadashi's chest with a drunken giggle.

Words fail Tadashi—not necessarily for the first time and certainly not the last, all as a direct result of Hiro—as he swallows heavily and awkwardly pats Hiro's head.

A spade is a spade. He's been kissed by his little brother. His contagious little brother.

Baymax seals the deal: "Oh, no."

Tadashi sighs, letting his eyes fall shut. "Thanks, Hiro." Who is now snoring into his shirt. "But we'll both be regretting that in the morning."

He curls around Hiro in their nest of blankets, and the last thought on his mind as unconsciousness takes over plants dread in his stomach.

Aunt Cass'll get a kick out of this.

-0-

Honey Lemon is back in the lab on Monday, looking pale and sickly, yet chipper and light on her feet despite that. Her doctor gave her the clear that she's no longer contagious, so leftover fever or not, she's eager to answer to the call of science.

(And no, she isn't going to develop a new formula in the name of revenge against hell raising siblings who trade saliva with strangers then borrow her favourite gloss, thank you very much.)

"Do my eyes deceive me, Honeyy!" is Fred's chipper greeting when she enters the lab. "You're back! Just wasn't the same without you."

She's been out of action only for a few days, but his sincere grin warms her heart. If Fred wasn't such a darling, she doesn't know who is. She might've pecked his cheek if she weren't so embarrassed from the events two days prior.

(Perhaps she should kiss Hiro's head from hereon out, not his cheek. Anything to minimalize the risk of passing on a deceptively contagious disease in the future.)

Wasabi smiles warmly as she returns to her chemistry table, fiddling absently with a wrench. "Now, you're sure you should be out of bed today?" he asks tactfully, paranoia lacing his words. "That's still a fever you have, Honey. Maybe Baymax could double check, be better safe than sorry—"

"No can do," Fred pipes up, "Baymax is otherwise engaged."

"Tadashi's out sick, too," comes Gogo's input. On cue, she darts past the chemistry station on her pre-modified bike, helmet discarded. "I said I'd take his work home for him. Hiro, too."

"Whoa, slow down there, Honey!" Fred yanks back the head of his mascot suit, his expression scandalized. "Look, we all know the little guy might have a thing for ya, but you can't eat your cake and have it. Not unless you're anti-hero material—"

"Excuse me?" Honey's eyebrows shoot upwards. "Giving it to Hiro was an accident, but I never went near Tadashi."

Gogo quirks an eyebrow. "He didn't borrow your gloss? Or glass? Any indirect lip contact?" Three shakes in the negative. "You're absolutely sure? Look, no one's judging, but if you didn't give it to him, then who ... "

In unison, three more sets of eyebrows elevate, and the silence is deafening.

Ultimately broken by Fred.

"Y'know, I hear a lot of people would be inconvenienced by turning into fire-breathing lizards." He shoots Honey a hinting grin. "So y'know, in the sake of revenge, it's food for thought."

She smiles tersely, theorizing the benefits of such a defense against genius brothers with a grudge.

Forget Hiro, her end will come by Tadashi's hand.

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Author's Note: Now I kinda want to write the inverse: "So, I hear somebody's been putting their lips all over you." "Otōto, please—" "Answer me!"