A/N: Prompted by umbrellaless22 on Tumblr, "Johnlock, school AU. Sherlock knows John wants to be a doctor, so he decides to help John get some practice. Like by actually injuring himself."

Sherlock scales the terrace, mindful of the winding ivy, out of bloom, that is wrapped around the crosshatched wood. His messenger bag taps at his knee with each upward motion of his legs, and his hands feel numbed at the tips with the chill of the morning, the dew on the grass below turned to frost.

He uses the tab left under John's never-locked window to pry it up, and then slide it fully to the top. He slips in gracefully, his school uniform getting a couple white paint chips on it as he climbs inside. He dusts off his trousers, closes the window behind him, and comes to sit beside John on his bed.

"John. Wake up," he says, shaking his only friend by the shoulder.

John stirs, rolling with a grunt onto his back. He glances at his clock. It's just after five thirty, and about an hour before dawn. He licks his dry lips to wet his mouth (left open in sleep) and snorts as he rubs his nose. "Jesus. Sherlock, school's not until later. My alarm won't even go off until a while yet. What are you doing here?"

"I need your help with some of my biology homework. I forgot about it last night because I put it off. And I am already doing poorly in the class because it slips my mind to turn my work in on time," Sherlock explains with a sigh. "And while I understand the material, it would help me get this done in the necessary amount of time if you would aid me."

John sighs heavily and rubs at his eyes, his face. He sits up, and Sherlock finds with a start that John sleeps in pajama pants, but no shirt. He swallows, tears his eyes away. John is nicely built thanks to the rugby he often partakes in. Sherlock hadn't noticed until now.

"Are you going to help me, or not?" he asks as John gets out of bed and picks up a t-shirt off the floor to put on, the chill leaking in from the window.

"I will if you close that," he says, pointing. "And give me a minute to go use the loo."

Sherlock nods, and John stumbles off in the darkness of the house to use the bathroom next door to his room.

After the window is shut, Sherlock lays out his homework on John's small desk in the corner. He takes the chair and starts scribbling furiously, writing down at least half the answers on the page.

When John enters, he kneels before the desk and takes up a different sheet, referring back to Sherlock's textbook as he fills out the rest, easily forging Sherlock's handwriting after years of being so familiar with it, and having to write in it a few times to save Sherlock's arse, much like now.

They finish in twenty minutes, and then John yawns. He glances at his clock. "No time to go back to sleep," he sighs. He looks at Sherlock, whom is filing away his papers and slotting folders, notebooks, and his textbook back into his bag. "Look, I'm going to have a shower. I suggest you head home."

Sherlock doesn't want to. He wants to stay here with John until they can walk to school together, like the always do. "Can't I stay? It's more efficient. I'm going to walk with you anyhow."

"Yeah, but you can't be seen leaving my room with me! My parents will wonder."

"You parents don't get up for work until you have already left. Why can't I stay?"

John flushes. "Because I come into my room naked to get dressed."

"Get your clothes now and take them into the bathroom with you," Sherlock shrugs. "I'll rest my eyes on your bed while you get ready. Then we can eat a quick breakfast together, and be on our way."

"We aren't normal," John mutters under his breath, thinking he's going unheard by Sherlock, as he collects his uniform, underwear, socks, and shoes and takes a clean towel from the closet in the hall to bring into the bathroom with him.

Sherlock doesn't mind waiting. And they aren't normal; Sherlock knows that. But since when does normal suit either of them?

John is merely seventeen (Sherlock is not yet that age; his birthday is later than John's), but he knows he wants to be a doctor, and specifically a medic in the army. He wants to serve like many members in his family have, and he is fascinated by everything medical about the human body and its functions. And he wants to help people.

Sherlock, on the other hand, is fascinated by everything regarding crime and forensic science. He wants to be a detective, and specifically a consulting detective separate from the rules and regulations of the police. And he wants to solve puzzles.

Their peers are only interested in graduating, drinking, sleeping with each other, and going to university to "find themselves." So no, they are not normal. Their interests in career are completely out of the norm.

And their bond is stronger than usual friends' bonds. They sometimes do things or act a certain way that their peers would ever act toward one another. But John doesn't seem to mind; he seems more amused than irritated by it, most of the time. And Sherlock wouldn't have their relationship any other way.

It would be too boring otherwise.

#

On their way to school, Sherlock notices a few toast crumbs left on John's jacket. He stops him and brushes it off for him.

"Thanks," John says with a slight pucker of his brows. He's smiling soon afterward. "That would've been embarrassing."

"It was annoying me," Sherlock shrugs, continuing to walk forward.

"Here, actually, you have some dandruff on the back of your neck," John replies, looking Sherlock over for any crumbs of his own and finding the white specks on his dark jacket instead. "Probably shaken loose when you were lying on my bed." He brushes it off in turn, once Sherlock freezes in place for him. "There. Now we're both clean."

"Thank you," Sherlock murmurs, "You always have my best interests at heart, John."

"Yeah, well. I know you have mine in mind, too, when you care to stop and realize it." And he grins.

Sherlock gives a small smile in return.

#

"John," Sherlock inquires at lunch as they sit in the sun, soaking up what little heat they can get before it retreats again behind the clouds, "May I sleep over this weekend?"

"I don't see why not," John shrugs as he takes a bite of his sandwich and adjusts the way his gray dress slacks fit atop his thighs, moving the seam inward. "My parents don't care when you sleep over. They find you charming. Can't imagine why," and he smirks as he finishes off his lunch.

Sherlock solely has a bottle of iced green tea for his lunch. He doesn't eat much. It worries John often, and Sherlock selfishly likes to suck up and swim in John's concern like substitute nourishment. No one else cares about him. His brother hardly does, and certainly his own parents don't care what he does, as long as he doesn't get killed. The other teens in their school poke fun at him behind his back, harass him, and ignore him. John is all he has.

He shrugs and sips at his tea. "Me either. Still, it's convenient to know I'm welcomed any time I please."

"Almost any time. Coming into my room in the wee hours of the morning was pushing it," John scolds. "I should have kicked you out this morning, told you to sod off. Don't know why I didn't."

"Because I am your friend, and you care about me," Sherlock answers, taking the statement literally.

John smiles at that. "I guess." He drinks the reminder of his water bottle and stands to go recycle it. "Heaven help me."

#

John's house is too cramped for Sherlock to have much more option than the sofa downstairs, the floor beneath the window of John's bedroom, or John's bed.

John always offers his bed. And he usually takes a spot on the floor, or brings his pillow and blanket downstairs to the sofa. But he likes to talk to Sherlock, so he remains on the floor tonight.

But it's chilly, much colder than usual. He shivers where he lies on the carpet, and, unable to sleep well, Sherlock glances over the side, hands braces on the ledge of the mattress, and tilts his head. "John? Do you want to com up to the bed?"

"What, and s-sleep with you?" he asks, wrinkling his nose at the idea. His teeth chatter.

Sherlock shrugs. "Yes. What else would I mean? It is such a big deal?"

"Yeah, it is –" John begins, but cuts himself off with a sigh almost immediately. "Never mind. I'm sh-shivering too much to care." He visibly shakes as he stands and picks up his blanket and pillow. Sherlock scoots over in the small bed, and John slips in beside him. Much of him is very cold indeed, and Sherlock feels gooseflesh rise in response to John's arm and leg brushing his. "Huh. Warmer already. You've always radiated more body heat than me."

Sherlock shrugs in response. They both lie and face the ceiling for a while, both of John's hands lax on his abdomen, both of Sherlock's at his sides, both pairs atop the covers. John blinks a few times. He wants to sleep, but he's finding it difficult.

So he talks instead. "After we graduate, I'm going straight to the military for training, and then to med school, when my service can help pay for it. And then, who knows? Maybe they'll ship me to Afghanistan, or Iraq."

"I hope neither. And if you are sent abroad, then you better come back unharmed. I won't chance losing you, you know," Sherlock states very quietly and sternly, his jaw set.

John glances over at him, surprised. "Come on, I can't be in that much danger. I'll only be a medic. I might never make it above private in rank. It will be fine. Plus, how can we know if we'll even be friends that far into the future? I mean, I would love it if we were, but we can't know. We might go our separate ways."

"We will be," Sherlock replies swiftly, seriously. He turns onto his side and faces John, reaching out and grasping his hand, giving it a nearly too-tight squeeze. "And if we separate, we're going to find each other again. I will look for you."

Somehow, it's comforting. John softens his face to an easy smile. "Yeah, okay. I'll keep in contact, and I'll find you, too, every time I'm on leave."

"We can get a flatshare together," Sherlock suggests as he releases John's hand.

John huffs a quiet laugh. "Sure can. I'm the only person who could stand to live with a prat like you."

"I'm not a prat."

John cracks up again, snickering to himself. "What? Yes, you are! You just called a girl out on her weight today, and then told her that her boyfriend was cheating on her."

"He is. I sit behind him in maths. He flirts with the girl across the aisle from him, and sends her sexual texts, implying that they have done or are going to do something together."

John shakes his head, grinning. "You're impossible. No wonder I'm your only friend. You offend everyone else."

Sherlock goes silent. He looks away, shifting over onto his other side.

John's smile falls when he realizes what he's said. He blinks, moves to prop himself up on one elbow. "Sherlock? Hey, I didn't mean that. I'm sorry. I know it's not easy; I've fought for you against bullies before. I've knocked in boys' teeth for bad-mouthing you in my presence when you weren't around, and you never did anything to provoke any of them. I just meant…" He sighs roughly. "I don't know what I meant. I was just teasing you. I'm sorry," he repeats. He touches Sherlock's shoulder. Sherlock acts like he's twenty-nine sometimes, but he's only sixteen. He's a vulnerable, awkward teenager just like all the rest, deep down.

There's a pause, and then, finally, Sherlock leans back a bit to peer over his shoulder at John. "…Why are you my friend, John?"

John frowns. "Because you simply are? I don't know. I have other friends, a whole slew of them, but you're my best mate. I've known you for ten years now, pretty much since we started primary school. You're my next-door neighbor and my first friend when I moved in. You've always been incredibly brilliant; you read things about me just by looking at me when you saw me over the wall between our houses. You and Harry don't get along, but she actually doesn't mind you, which is a feat, trust me. My parents like you, and they don't always like my friends. So I don't know, really. You've just always been there, and even through the years as we've changed interests and matured, I still think you're the most genius person I've ever known, and I'm… I'm proud to call you mine – My friend."

John blushes at the slip-up, but Sherlock takes no notice.

Sherlock rolls onto his back and peers up at the blond teen, scanning his face with his eyes. "I want to do something for you."

"Eh?" John says, smiling slightly. "What for? You never do anything for others. It's one of your quirks: you don't like doing things for others so that you don't disappoint, and don't waste your time."

Sherlock shakes his head. "I'm making an exception. What would you like?"

John shrugs. "I don't know. Nothing. You don't have to, anyway." He looks over Sherlock at the clock on his bedside. "We should sleep. It's after one a.m."

"John," Sherlock murmurs. "Let me help you practice to become a doctor."

"What, like, help me study?" John asks, frowning.

"I have a few methods in mind. May we start tomorrow?" Sherlock wonders.

"Um… No, I'd rather not. Maybe after school, during the week? We could then, I guess. Yeah, that works. Thanks," he adds, nudging Sherlock's arm. "You're the best, Sherlock, you really are. Even if we sometimes get into the worst fights, and you're sometimes an ass, you're actually the best."

Sherlock's smile is bright; a rare sight. John enjoys it as the last thing on his mind before he settles back down and is able to sleep.

#

Sherlock comes over to John's house Tuesday afternoon. When John answers the door, he lets out a small scream. Sherlock is holding up his arms in front of his chest, bent at the elbow and fingers curled loosely in his palms. There is crimson liquid trailing down from four cuts, two on each arm below the wrist, dripping at the point of his elbow and splashing onto the cobblestone path leading to John's door.

"Sherlock! What happened?"

"I wanted to help you become a doctor," Sherlock says effortlessly, and that makes the image of him bleeding out from the arms all the more unsettling. "So I injured myself."

"S-stay there!" John panics. He runs back into his house, finds an old towel, and rushes back. He wraps it around Sherlock's bleeding arms and holds him, guiding him into the kitchen. Thank God the downstairs is mostly wood-floored and tiled, easy to clean.

He runs water, finds his mother's first-aid kit, and goes about tending to Sherlock's wounds, cleaning the cuts, spreading antibiotic ointment with an ear-cleaner over the irritated skin and wrapping gauze around the vertical gashes. They are about five to six centimeters each in length, give or take a centimeter on a cut or two.

"Sherlock, why did you do this to yourself?" John pleads, looking up into Sherlock's downcast eyes as he gently holds his unharmed wrists.

"Isn't this the best way to learn how to give people medical attention: by having hands-on experience?" Sherlock questions aloud, his voice calculating and soft.

John's face contorts into something empathetic and tragic. Sherlock only glances once, but when he sees it, he feels a flood of shame and looks away again, tearing his wrists out of John's grip, rolling down his sleeves over the bandages.

"No… No, Sherlock, that's not – It might seem like a good idea, but hurting yourself? That's – no. It's not a good way to learn. Not like this."

"It's unorthodox to cause it myself, I know, but it works, doesn't it? You treated me well, just now. Like a true doctor," Sherlock defends meekly, but he can hear how his poise is waning. "It shouldn't matter, anyhow. I didn't go deep; only broke platelets, not any veins. It will heal without scarring."

"That's not the point!" John raises his voice, and Sherlock, despite being the taller of the two, shrinks back. "I don't want you bleeding for me! That's not right, Sherlock."

"But I don't mind bleeding for you," Sherlock mutters stubbornly, coldly. "What does it matter? I'll be fine. I knew you could heal me. It's no worse than a cat scratch, and will be less prone to infection, since I used a sharp, clean knife."

"Sherlock…" John tries again, attempting a gentler approach, "I'm touched you wanted to help me, but hurting yourself is not the way to do it. I thought you meant we would study medical textbooks together, go through flashcards. Had I known you meant this, I wouldn't have agreed to your help."

Sherlock peers up and smiles. "Look, John, you're even talking like a doctor, now. Good. You can't get angry with your patients if they hurt themselves; you have to speak gently, understandingly. I knew you would."

John gapes. "Was… was that a test?"

"Of course. Being a doctor is not only about treating the physical, but tending to a patient's emotional wounds as well. Which you just did exceptionally with," Sherlock relays assuredly.

"This… this is really messed up," John murmurs.

"It's fine, Dr. Watson," Sherlock answers. "You'll be the best medic the British Army has ever had."

John should think Sherlock has gone mad. But, inexplicably, he knows he's not. This is just another of Sherlock's unusual methods of showing that he cares, and is trying to be of use.

"Yes, I might be. But please, Sherlock, promise me you won't hurt yourself again?" John implores as he takes Sherlock by the shoulders and looks him directly in the eye.

The dark-haired boy can't deny him. He nods. "Yes, yes, all right. I won't."

"Good. Thank you," John sighs with relief.

#

On Friday, Sherlock is held back after school is out due to a fight.

Sherlock's parents are unavailable. John's come instead, Harriet reluctantly in tow.

"Aren't you a bit old to be getting into schoolyard fights, young man?" Mrs. Watson scolds with her hands on her hips.

"He was asking for it," is Sherlock's sole reply.

The parents chat with the headmaster and John takes Sherlock to the infirmary, the nurse gone, but her supplies there. He patches Sherlock, dabbing hydrogen peroxide on the cut formed around his bruising eye socket, and helps clean his busted lip.

"He looks worse. His parents took him to the hospital," Sherlock brags, but shuts up when John sends him a look.

"This better not be because I told you not to hurt yourself, and you still want to give me hands-on practice," John warns as he spreads ointment on Sherlock's purpling skin and the streaks of red on pale skin. It makes his wounds look more intense, and inaptly greasy. But it will help the healing process, and help protect it.

Sherlock sighs. "You're not as stupid as you look. But I should have known; you know my habits, and are above average intelligence."

John throws down a cotton ball and shouts, "So you did pick a fight because you wanted to get injured and have me fix you up! Dammit, Sherlock, you can't do this!"

"I don't care if I'm hurt if it means you become a good doctor!" Sherlock retorts. "I don't mind! It gives you the best practice, apart from volunteering at the hospital – but even then you aren't permitted to do as much for others as I am giving you opportunity to do – and it's convenient and efficient, having me injured in a controlled environment, nearby to you, always, and within care."

"It sounds logical when you put it like that, but do you realize how it makes me feel, seeing my best friend getting hurt all because he thinks it would help me? How would you feel, Sherlock, if I stole something or smuggled drugs or blackmailed someone just to give you a puzzle to hone your detective skills? –Or, worse yet, what if I killed someone else and then myself to give you a good murder-suicide crime, and a couple bodies to study at your leisure, because I would be nearby, someone you know, and convenient?" John throws back.

Sherlock stumbles off of the examination cot and gawks at John with wide eyes and considerably parted lips. "…I would… I would feel ill. I wouldn't be able to –" he swallows. Picturing John white and cold, rigor mortis stiffening his joints, his face contorted in pain of death, his eyes glossy and unseeing; picturing John's young, able body bruised with livor mortis as well, coagulated blood pooled around his body, soaking his bright blond hair; thinking of John capable of cold-blooded murder, of taking away his own life, all for Sherlock's sake… Sherlock's eyes start to water. "I would not like that, no."

"No," John says lowly. "No, I don't think you would." He sighs, his anger receding. "Sherlock, please. I know you're reckless by nature, and your intentions are good, but I don't like wondering what you must think of yourself to hurt yourself so easily, and just for me." He softens and reaches out, gently touching Sherlock's cheek below his injured eye. "And I don't like seeing you looking mangled, either. It ruins your handsome face."

Sherlock could smile. He doesn't. "You think I'm handsome, John?"

"Shut up," John replies, turning to hide a slight blush and clean up the mess of medical supplies and bloody cloths. He dumps it in the rubbish bin and when he returns to Sherlock's side, Sherlock looks apologetic and sullen. John offers a tiny smile and drapes his arm over Sherlock's slender shoulders, having to reach up quirt a bit to get there. "Come on. We need to get back to my parents, now, and go home. You're staying over again; no buts."

"I wasn't going to disagree," Sherlock utters clearly, feeling in better spirits, despite the stinging throb on his face.

#

Two months later, they on summer holiday, and having a small fire in the pit on John's patio. Sherlock roasts a sausage on a skewer, turning it over.

"Hey, don't stand so close! And why do you have one of the older, shorter sticks?" John says while his parents and a few others chat and drink together inside, playing cards at the kitchen table. There are some of John's other friends around the fire, and some playing ball in his small yard, using circles drawn in chalk on the stone walls on either side as goals.

"I know what I'm doing," Sherlock reassures. He brings the sausage closer, squishes it, and shakes his head. "A bit longer," he amends.

John sighs. "I worry about your love of fire sometimes, Sherlock."

"At least I am not a pyromaniac going around and committing arson," the taller teen grins wickedly. He chuckles and his sausage wobbles with the vibrations.

"Hey, careful, or it'll –" John warns, but it's too late. Sherlock cuts off mid-laugh as the sausage tips forward, taking him a bit closer with it as it slides off the end, lost to the crackling fire.

And then Sherlock's sleeve catches at the elbow where he rolled it up but didn't keep his cuff buttoned, leaving it susceptible to drooping too low.

"Jesus Christ!" John cries, reaching for his drink beside him and dousing the fire on Sherlock's arm with it.

There is a spot of hair missing on Sherlock's forearm, along with the beginnings of a first- or second-degree burn. Half of the guests stop and look at the commotion. John's mother gets up and instantly is by Sherlock's side as Sherlock stares, eerily silent, at his forearm near his elbow.

Thankfully, it's no more than a few blisters that will heal up nicely, given proper time and care. But that doesn't stop John from treating to them like he would a worse burn, and proceeding to yank Sherlock into his bedroom.

"I can't believe you did that, or that it even happened! What were you thinking? Were you trying to 'accidentally' get burned just so I would play doctor with you again?" John accuses sharply, and Sherlock shakes his head.

"No! John, no. I told you I wouldn't do that again, and I haven't! It was a sincere accident, and I was being careless, but not intentionally so! Please, you have to believe me," Sherlock beseeches, twisting his hands together anxiously.

John blows air out his nose in frustration. "Okay. I believe you. I'm just – just a little paranoid after the whole fiasco a couple months ago."

"I've learned my lesson there, John, I honestly have," Sherlock states undoubtedly. "You must trust that. I know not to pt you through that again. Every time I think of it, I think of what you said about giving me a crime, and I picture you dead, and I stop cold."

John feels a pang of guilt for that. He didn't know it would affect Sherlock too much when he said it. But if it works, then he can't feel too bad. It keeps Sherlock from hurting himself on purpose, at least. He sighs again and steps forward to bring Sherlock into his arms. Sherlock goes rigid and doesn't return the embrace. "I do trust it. You just scare the bloody hell out of me sometimes, Sherlock."

Sherlock forces himself to actively blink. Then he brings his arms around John's shoulders and closes his eyes. "I never want to do anything to push you away again. But you must admit, practice makes perfect."

John snorts without humor, pulling out of the hug. "Sherlock," he cautions.

Sherlock frowns. "Not good? Was the joke made too soon?"

"Not good, yeah, just a bit. Definitely too soon," John confirms.

"…Sorry."

"It's okay. You're learning, at least," John adds with a pat to Sherlock's shoulder. "Now let's get back out there before everyone starts talking."

"…What would they talk about?" Sherlock asks, puzzled. He fails to see the implication that could be caused of them simply talking.

"We've been absent from the party to my bedroom for long enough that they might think we're snogging or something," John mumbles, his ears burning.

"Ridiculous. They have all seen you date girls over the years. You would have no interest to do that with me, and they know it," Sherlock replies.

"You'd be surprised," John sighs again.

The rest of the gathering goes off without a hitch. At least, only three people leave because of something Sherlock says to them, and no one else gets wounded.

###