"Why are we studying?" Yabuki Hayato wants to know. "It's Sunday, Ryu. The sun's shining and I want to go get takoyaki."
Odagiri Ryu looks at the rolled-up stack of notes in his hand and contemplates hitting his best friend over the head with it. He manages to refrain from doing so on the grounds that Hayato will use it as an excuse to launch a counterattack, and then they'll never get anything done. "We had lunch less than ten minutes ago," he points out, "and you haven't even opened a textbook since then. Fail tomorrow's chemistry test if you want but don't drag me down with you."
Hayato sighs and pulls himself up into a sitting position so he can at least pretend to be alert. Chemistry has never been his best subject, though he does have a remarkable knack for making things explode. But if Ryu fails the test, the only thing exploding will be his father, which is why Hayato dutifully volunteered his services as study partner. He'd thought spending the day with Ryu would be fun - he just hadn't considered there would be so much actual studying involved.
"I'm not going to fail," he defends himself. "I have notes too, you know. Look at all the work I did this morning."
To be fair, there is indeed a battered notebook sitting on top of the stack of chemistry texts, and Hayato has been scribbling in it on and off since Ryu threw his carefully constructed revision plan at him and said, "Here. Get started." What Hayato knows and Ryu only suspects to be true is that most of the pages are taken up with pictures, where Hayato has gotten bored and started doodling.
Ryu can't complain because he doesn't have the most comprehensive set of notes in the world either, though his drawings are only in the margins and are at least vaguely related to chemistry in some way. If he does end up getting expelled from high school before graduation, he thinks he could probably make a decent living drawing the continuing adventures of a group of atoms. One of them even looks like Hayato - the one with its shirt open right down to its round little waist.
"Maybe you took notes," Ryu says, crossing his arms, "but how much do you remember?"
Hayato looks at him blankly and says, "Of what?"
Ryu picks up the last text they'd been working from before breaking for lunch and turns to the relevant chapter. "Chemical bonds. What do you remember?"
Hayato smirks. "Definitely more than you." He leans lazily back against the bed and waits to be challenged.
Ryu doesn't disappoint him. "Prove it."
"If I do, can we have takoyaki?"
"I'll think about it."
Never mind that the contest is unfair and Hayato can't technically prove that he remembers more than Ryu - it doesn't matter if neither of them wins, because it's the competition between them that inflames their relationship, the sparks that drive them both higher till their boasts are beyond ludicrous and their excitement reaches fever pitch. There's only one way this can end, and it isn't a traditional study method.
Hayato sits up straight, dons a pair of glasses he pulled, seemingly, out of thin air, and slips into teaching mode. "Covalent bonds," he declares proudly, and waits in satisfied silence for Ryu to say something.
The other boy is doing his best to hide a smile behind his notes. "That's a start. Tell me what they are."
"Uh..." Hayato scrabbles around in his memory. "Give me a minute, I think I drew a picture of one earlier." He reaches for his notebook.
"Not allowed." Ryu bats his hand away. "No notes."
"Then you can't use yours either...and close that textbook too, or I'll have to take it away from you."
The implied threat in Hayato's voice sends delicious shivers down Ryu's spine. He closes the book and casually tosses it away from them both, sending his notes after it. He's fairly certain he remembers enough to tell whether or not Hayato is making things up, and if he doesn't, the other boy will never know. He stretches out on the bedroom floor, pillows his hands under his head, and waits to be enlightened.
"Now, Hayato-sensei will tell you all about covalent bonds." Hayato looks down at Ryu, almost losing his glasses in the process. "When atoms bond to form molecules, there are various different ways that they can combine. In a covalent bond, the atoms share pairs of electrons."
Surprised that Hayato has actually managed to remember something from their study session, Ryu nonetheless refuses to compliment him for it. If he does, the lesson will be over. "Of course they do," he says carelessly. "Everyone knows that. Give me an example."
Hayato pushes his glasses back up his nose and frowns. He's about to tell Ryu it's *his* turn when he catches sight of the periodic table, which is lying - slightly crumpled - under his friend's elbow. Seeing hydrogen gives him an idea.
Ryu watches Hayato's expression change from petulant to jubilant and hopes that this isn't going to lead to the bedroom exploding in some bizarre act of experimental chemistry.
"Hydrogen atoms have one electron," Hayato says. "You can follow this so far? I'm not going too fast for you?" He wags a finger at Ryu and adds, "You shouldn't glare at your teacher like that. Anyway, to complete its outer shell and become stable, hydrogen needs *two* electrons."
Ryu nods mechanically and starts to close his eyes; he knows all this already, and has a pair of large-eyed chlorine atoms in the margins of his notes to prove it.
Hayato's not in a position to complain about anyone else sleeping through class, so he decides to keep Ryu awake with a practical exercise. "Pretend I'm a hydrogen atom and this," he holds up his left hand, "is my electron."
"What about the electron attached to your other arm?"
"That's not there. I only have one and poor me, I'm unstable."
"Poor you," Ryu agrees, trying hard not to laugh.
"Poor you too, because you are also a lonely hydrogen atom with one electron. Raise your right hand."
Ryu grumbles, because to do so means he loses his pillow, but he plays along anyway because he wants to see where Hayato is going with this. "Here." He sticks his hand out and waits for the punchline.
Hayato grins triumphantly, seizes Ryu's right hand with his left and declares, "We are now a diatomic molecule!"
"We are." Hayato nods and squeezes Ryu's hand tightly. "We're sharing our electrons to become stable. That's my example of a covalent bond."
Ryu squeezes back, extending his fingertips to brush just below the wrist of Hayato's shirtsleeve. "Do you have any more examples?"
"Can I look at my notes?"
"Then, can I look at your notes?"
Keeping their hands linked, Ryu passes his notes over then remembers, too late, about the atom drawings of his friends. Hayato looks delighted with the pictures, though.
"That one's Take, right? I know that headband. And on the next page, the really handsome one with the good hair, that's me, right?"
Ryu checks to see which one he's referring to. "Yeah, that's the sodium version of you."
"Sodium me looks a little chubby."
"That's because you've got an extra electron," Ryu explains. "You're going to give it to the chlorine version of me."
"Chlorine you could do with some food," Hayato agrees. "He's even skinnier than real you."
Ryu ignores the jibe about his weight. "Sodium gives the extra electron to chlorine and together they become sodium chloride. That's my example of an ionic bond."
"My example was better than yours," Hayato says. "Mine had actions."
"You're the sodium atom. If you want to bond with me, you'll have to give me an electron."
Ryu thinks that may have been possibly the strangest come-on he's used in his life, but it seems to work because Hayato removes the glasses and gives him a slow smile that promises to keep them away from the books for the rest of the afternoon.
"So, Ryu, you want me to give you something and then we'll be bound together for life, is that right?"
"Don't make it sound like I just asked you to propose, idiot!" Despite his cross words, Ryu is laughing. "If my father really does send me overseas, he might dissolve our bond."
"Then we'd better improve our chemistry," Hayato quips. His father and brother are both out, thankfully, and they don't have to worry about interruptions. Just in case, he locks the bedroom door.
Ryu nods approval and Hayato sits back down next to him on the floor, gazing at him thoughtfully.
"Saa...what should I give you? You chlorine atoms are so hard to please."
"At least we're learning something for the test," Ryu says with a sigh.
Hayato kicks out at the stack of textbooks, which collapses with a crash, and says cheerfully, "Hayato-sensei will make sure you know all about bonding before the day is over."
"And nothing else."
"We don't have that kind of time, Ryu."
Maybe Hayato's right about the time but he's in no rush, caressing Ryu's face with tender, teasing touches that lightly skim the surface of the skin before darting away. They're so used to carrying battlescars from fights that soft, careful motions are now second-nature, neither of them wanting to accidentally press on a bruise or re-open a cut. The pain would be worth it, but utterly without point.
Ryu waits impatiently for Hayato to finish his practical example of ionic bonding, somehow managing to keep his hands idle by his sides, only just resisting the urge to lever his best friend up on the bed and tear off his shirt. He eventually gets his electron in the form of a kiss, not teasing now but urgent, a press of lips so forceful that Ryu thinks Hayato may be physically trying to donate body parts in the name of science.
"There," Hayato says breathlessly. "Ionic bond. Does my precious student understand or should I do it again?"
"Your precious student thinks you should shut up and get on that bed before it's tomorrow already and we actually have to go take the chemistry test."
Hayato scrambles up and says with a wink, "We're bonded now so where I go, you have to follow." There's no argument from Ryu, not until Hayato adds, "Which means when I go to get takoyaki later, you have to follow. Uh...and pay."
"Why do I have to pay?" Ryu demands to know.
"My fee for being such a wise and understanding teacher."
Ryu gives him a tight smile. "Then, *Hayato-sensei*, I'm going to make sure you really earn your money!"
It isn't until much later, when the sun is setting and Hayato is curled around him in a blissful sleep state, that Ryu remembers just how many books they still have to get through if they don't want to flunk the test. Then Hayato opens his eyes and gives him a lazy smile, running one hand down his chest and letting it linger on lower and more mobile parts, and Ryu thinks that the test can take care of itself.
Maybe they'll both fail...but their chemistry is perfect.