The air in Oota's apartment had changed. Usually, it felt like a cool, still pond—undisturbed and very clear. But with Haru sitting less than a foot away, the atmosphere felt like it was beginning to simmer. It was the "Body Tea" versus the "Fresh Bread" once again, and Oota was losing the battle for territory.
Oota stared down at his notebook, his grip on his mechanical pencil so tight that his knuckles were turning white. He could feel Haru's gaze. It wasn't a casual glance; it was the kind of heavy, focused stare a sculptor might give a slab of marble, or a baker might give a tray of rising dough. It was a gaze that expected something to happen.
"Are you going to stare at the paper until it catches fire, or are you actually going to solve the problem?" Haru asked. His voice was lazy, draped in a smugness that made Oota's skin itch.
"I'm thinking," Oota snapped. "Calculus requires a quiet mind. Something you clearly don't understand."
Haru chuckled, a deep sound that seemed to rumble through the floorboards. He leaned back in Oota's delicate wooden chair, which groaned under his muscular weight. "A quiet mind is just an excuse for a slow one. You're stuck on the chain rule, aren't you?"
"I am not stuck," Oota lied. He was very stuck. The numbers were swimming.
The problem on the page looked like a cryptic message from a hostile alien race:
Find the derivative of:
f(x) = (3x^2 - 5x + 2)^4
Oota's brain felt like it had been stuffed with damp wool. He was trying to maintain his "Body Tea" composure—staying earthy, staying grounded—but Haru's presence was like a high-voltage heater placed too close to a delicate plant. He could smell the lingering scent of cinnamon and burnt sugar on Haru's skin. It was distracting. It was delicious. It was annoying.
"Here," Haru said suddenly.
Before Oota could protest, the baker moved. He didn't just point; he shifted his entire body. Because the table was small and Oota was "slim," Haru's large frame effectively boxed him in.
Oota froze. The 13cm height difference was even more apparent when they were sitting. Haru's shoulder was broad and solid, draped in that thin black t-shirt that left absolutely nothing to the imagination. As Haru reached across to grab a spare pen, his chest brushed against Oota's shoulder.
It wasn't a hard impact. It was a soft, fleeting graze of fabric and muscle. But to Oota, it felt like being hit by a low-frequency shockwave. The heat coming off Haru was intense—the "Fresh Bread" was straight out of the oven.
"Look," Haru murmured. He didn't move away. In fact, he seemed to lean in closer, trapping Oota between the table and his own massive physique. "You're treating the function like a single entity. You have to break it down. Think of it like a croissant."
Oota blinked, his breath hitching. "A... croissant?"
"Layers, my boy," Haru whispered, his voice vibrating right next to Oota's ear. "You start from the outside. The crust. That's your power of four. You derive that first, then you move into the buttery center—the polynomial. And then you handle the filling—the cosine function."
Haru's hand moved over the paper, his fingers sure and steady. He wrote out the steps with a grace that Oota didn't expect from someone who spent their day punching dough. The LaTeX-style precision of his handwriting was irritatingly beautiful:
[(3x^2 - 5x + 2)^4] = 4(3x^2 - 5x + 2)^3 (6x - 5)
"See?" Haru's head was so close that Oota could see the individual strands of his dark hair. "You were missing the inner derivative. You were being too timid with the math. You have to be aggressive. You have to take what you want from the equation."
Oota couldn't even look at the math anymore. He was hyper-aware of the way Haru's bicep flexed as he wrote. He was aware of the scent of Haru's hair—something like cedarwood and flour. But mostly, he was aware of the weight of the silence between them, broken only by the sound of Oota's own frantic pulse.
It's the tea, Oota told himself desperately. I drank too much matcha this morning. It's a caffeine spike. That's all this is. It's not him. It's the caffeine.
Haru finished the problem, setting the pen down with a decisive click. He didn't pull back. He turned his head slowly, his amber eyes locking onto Oota's flustered face. A small, knowing smirk played on his lips. He had noticed. Of course he had noticed. Haru was a "Red Flag" for a reason—he smelled blood in the water.
"You're shaking," Haru noted, his voice a low, dangerous purr.
"I am... not," Oota whispered, though his hand was visibly trembling on the table. "I'm just... cold. My apartment has a draft."
"A draft?" Haru's smirk widened. He leaned in even further, until his nose was almost touching Oota's temple. He looked at the corrected math problem, then back at Oota. "The answer is perfect. You finally got it."
Then, his voice dropped to a level that made the hair on Oota's neck stand up. It was a gravelly, intimate sound that felt like a physical caress.
"Good ya... my boy."
Oota's heart didn't just skip a beat; it did a full-blown Olympic backflip. The phrase was so simple, so casual, yet the way Haru said it—like Oota was a prized possession, a successful experiment, or a particularly tempting dessert—made Oota's lungs seize up.
Oota scrambled backward, his chair screeching against the floorboards. "Okay! I get it! I'll do the next ten problems myself!"
Haru laughed, a rich, dark sound that filled the room. He leaned back, finally giving Oota some space, though the "Fresh Bread" scent still hung thick in the air. "Don't be so dramatic. You're acting like I just bit you."
"You... you're unprofessional!" Oota shouted, his face now a shade of red that would put a ripe tomato to shame. He adjusted his glasses with shaking fingers, trying to regain his "Body Tea" dignity. "You're supposed to be a tutor, not... whatever that was!"
"I'm a baker, Oota," Haru said, crossing his thick arms over his chest. "Bakers know when something is ready. And right now? You're definitely starting to cook."
"I am not cooking! I am studying!" Oota grabbed his textbook and held it up like a shield, hiding his face behind the thick pages.
Inside the safety of his paper fortress, Oota squeezed his eyes shut. His heart was still hammering against his ribs, a frantic thump-thump-thump that echoed in his ears. He tried to focus on his "Body Tea" mantra—calm, earthy, grounded, routine—but all he could think about was the heat of Haru's chest and the way those four words had sounded.
Good ya... my boy.
"Caffeine," Oota whispered to himself behind the book. "It's definitely just the caffeine."
Haru, meanwhile, reached into his bag and pulled out another pastry, the sound of the crinkling wax paper mocking Oota's attempt at silence. "By the way," Haru called out, "if you get the next one right, I might let you have a bite of this lemon tart. It's sour. Just like you."
Oota didn't answer. He couldn't. He was too busy trying to figure out how a math lesson had turned into a heart attack, and why, despite his better judgment, he was already looking forward to the next "Good ya."