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Summer after the first year of high school settles in slow and heavy. The Sagami grandparents are away, the house empty save for Aki and Shima, and Shima finds himself thinking that their ennui must be just as palpable as the tension growing between them. He isn't sure of the reason why, really, but Aki has always been volatile. So Shima figures he can sleep on the couch downstairs for a few days. Let Aki have their bedroom to himself. After all, it's only them... no rules. (No parents, Shima thinks with a pang, and then stops himself.)
Shima drags himself up from bed to search for Aki and tell him just this, but when he opens the door to step out, Aki steps in. They collide. Aki is naked, dripping wet with nothing but a tiny towel wrapped around his waist.
Shima has grown tall and gangly since winter break, and his brother seems suddenly so small. Aki's face is pressed to Shima's chest. When they awkwardly step past each other, they're both pink-cheeked. Aki has gotten his ears pierced; Shima's gaze lingers on the pretty rings as Aki moves towards the dresser to grab a change of clothes. His wet hair brushes Shima's chin. It's soft, and smells like Shima's shampoo.
But there's something else too, Shima decides, turning around again to watch his brother strip shamelessly naked, back to Shima as he dries off. Or, well, maybe Shima is the shameless one as he stares at Aki's body: slim shoulders, narrow waist, full hips, lean thighs. Shima follows the water trickling down Aki's legs, considering who will end up mopping the wet floor (not Aki), when realization hits him like an unexpected pre-rut: Aki smells sweet.
Aki, bent over to pull his boxers up his calves, finally snaps.
"I can feel you staring, y'know? What, something you haven't seen before?" It's meant to be a jeer, but it sounds oddly insecure, and the tips of Aki's ears burn red.
"You smell sweet," Shima just says, opening his mouth to taste the scent on his tongue.
The scent is nothing he's ever smelled before, yet at the same time, Shima feels certain he's known it for forever. That it's innately familiar, like the back of his hand or the sound of Aki's laughter. Shima doesn't mind it, really, but he finds himself overcome with an urge to place it. And as he steps forward, Shima is vaguely aware that maybe this is the alpha in him: the part that makes him more possessive than he ought to be.
"Have you been around any omegas?" he asks, knowing that can't be right. Aki is a beta. The only way he'd smell this sweet is if he slept with an omega, but Shima is sure that hasn't happened: otherwise, Aki would've rubbed it in his face the moment he came home.
Before Shima realizes what he's doing, his nose is pressed to his brother's bare shoulder. Shima's parted lips brush Aki's skin, tasting, and Aki gives an undignified squeak. The towel in his hands drops to the floor. It's fluffy... very fluffy, brand-new. Expensive. Aki has been shopping so much this month, working two jobs just for pocket money enough to come home with bags upon bags of luxury fabric, high-end clothes. It's almost as if—
"Sh-Shima?" Aki whispers. He sounds frightened; on instinct, Shima strokes his waist, crooning quietly. As his fingers splay across the taut skin of Aki's stomach, Shima can't help but notice that it's so soft. The smell is stronger now, an intoxicating sweetness that Shima trails with his mouth to—oh. Oh. As Shima nips Aki's swollen scent gland tenderly, disbelievingly, Aki whimpers. And the helpless little sound goes straight down to Shima's cock.
"Aki? You're an omega," Shima groans stupidly. His face feels hot. In Shima's hold, Aki shivers, squirming, and Shima is unable to suppress a growl as his grip around Aki's waist tightens enough to leave bruises. Then, as if some spell has been broken, Aki elbows Shima's ribs sharply. And Shima lets himself be shoved, half-relieved even though he's bigger, stronger. The alpha. Shima hits the wall with a grunt. His glasses tumble down, and they both catch their breaths.
When Shima presented in junior high, the nurse had told him his hormone levels were lower than those of most alphas (normal alphas, she hadn't said, but Shima could understand). Nothing major, she'd reassured him: it often happened to twins. He'd still get ruts, would have to be careful about being possessive, controlling... could command if he put his mind to it. But for the most part, Shima's brain would be wired like a beta's. Shima had liked that: calm, clear, rational.
Not-so-rationally now, Shima feels compelled to claim Aki. For a heartbeat, Shima imagines taking him right here. Right now: he could hold Aki down just like this, grind their hips together, sink his fangs deep into Aki's gland to mark him his. Shima's alone. Gulping thickly, Shima fumbles for his glasses. As blurs sharpen into clear lines, he sees Aki staring at him, pouting, chin ducked. When their gazes meet, Aki's eyes flit up and down Shima's body as he swallows, too.
It makes sense, Shima suddenly realizes. The signs have always been there: Aki has stayed so small since junior high, too small to be a beta... his mood swings, temper tantrums, clinginess. Shima'd overheard doctors telling their parents that twins were usually betas. That if one twin presented, it was nearly guaranteed that the other wouldn't. But nobody had ever said it was completely impossible. Maybe Shima had ignored the truth all along... afraid of what it could mean. Of what would become possible.
"So what if I'm an omega?" repeats Aki, sounding so lost and confused that Shima's breath hitches. No-one is here to help him the way Mom and Dad were there as Shima figured things out in junior high. The only ones they both have left now are each other. Squeezing his eyes shut, Shima presses a hand over his face to hide the color of his cheeks: a deep flush that would give away all the horrible things he wants to do to help his precious Aki.
"Nothing," Shima lies, "just surprised." His heart twists and throbs inside his chest. Like a monster, Shima is hit with a need to take care of Aki in so many ways. Ones he'd never considered before. And yet it feels almost right, natural, like breathing or thoughts about Aki always swirling in the periphery of his awareness.
"Uh, let me know if there's anything I can do to help," he adds. Shima's voice comes out hoarse, rough and husky. It startles him, and Aki blushes cherry red down the slender column of his pale throat.
"Y-yeah, okay," stutters Aki, casting his eyes to the floor at Shima's feet. "Whatever," he adds a moment later. But it has no edge to it, whispered as if just to prove that he can, and Shima stays leaning against the door as he watches Aki get dressed.
His brother is so lithe, dainty. Shima is very sure that Aki would fit perfectly against his own body, as if he's made just for Shima to protect. Shima's fangs prick inside his gums, too early for pre-rut. Yet, even as he tells himself he's imagining—wishing things, Shima can't help wondering—hoping if Aki's heat and his own rut will hit in synchrony. They're twins, after all... They're the only ones left for each other, now and forever.
It's a big empty house, and a hot summer vacation.
"''M gonna go get a popsicle, want one?" Aki asks, shoving past Shima. Shima grabs his elbow, then drops both of his hands to stroke Aki's little waist.
"Sure," Shima murmurs against his ear, "get me one that tastes like you."
And when Shima's mouth moves down to kiss the damp, sensitive skin at the nape of his neck, Aki shudders, but doesn't push Shima away... Aki tastes just as sweet as he smells: like strawberries ready for harvest, ripe and plump.