Posted originally on the Archive_of_Our_Own at https://archiveofourown.org/ works/10554668. Rating: Explicit Archive Warning: Underage Category: M/M Fandom: モブサイコ100_|_Mob_Psycho_100 Relationship: Kageyama_"Mob"_Shigeo/Serizawa_Katsuya, Kageyama_"Mob"_Shigeo/Reigen Arataka Character: Kageyama_"Mob"_Shigeo, Serizawa_Katsuya, Reigen_Arataka Additional Tags: Mentions_of_past_Serizawa/Shou, Unhealthy_Relationships_and_Dependency, past_emotional_abuse, Blow_Jobs, Facials, Voyeurism, Masturbation, starts out_sweet_and_gets_worse_over_time, Serizawa_is_a_broken_man Stats: Published: 2017-04-06 Words: 3831 ****** How to Love a Boy ****** by Gwappo, Motte_(Gwappo) Summary It takes much for Serizawa to feel comfortable in any situation, but luckily Mob is a helpful kid. Notes This one goes out to Nico, whose belief in SeriMob inspired me to try and convert y'all to this severely underrated ship. Hope you guys enjoy! See the end of the work for more notes The first time Serizawa enters Reigen's office he flashes back to the day he left his room: he's anxious and shaking, catching glimpses of a world so foreign it teeters on the brink of unreal. Back then he was determined to change its course, committed himself to the man who wished to become its new center. If necassary, Touichirou once told him, they'd keep the earth from turning to create a better tomorrow. Today Serizawa knows those words were lies. The memories of his actions sting sometimes when he lets them surface, but he's found another voice to lend him strength. "Bad experiences help us grow as people," Reigen says as he hangs up his suit coat, rolls up his sleeves. "Think of it as a bee sting, for example. The pain will fade after a few days, but the knowledge you gained will remain right here," he taps a finger against his temple, sits down in his chair. "You know you won't swat at bees with your bare hands again. Now, take a seat, please." Serizawa doesn't quite get the metaphor, but the prospect of seeing the boy who saved him again makes him hold his chin higher. =============================================================================== When Mob comes in for work that day, Serizawa waits until they're alone in the room to thank him. "For everything," he says, running a twitchy hand through his newly cut hair. "I was your enemy when we first met, but you still decided to help me. You and your master have been nothing but kind to me ever since I met you. I'm very thankful for that." Mob blinks up at him. He's so flat now, not at all like the boy he remembers shouting and screaming that day, all fiery eyes and clenched teeth. "You're welcome, but you don't need to thank me. I did what I thought was right." Serizawa smiles nervously, wringing his hands, and Mob's voice finally pitches upwards as he says, "I'm sure you'll do great. It's nice having you with us." He sits down at the coffee table and rummages through his backpack as Serizawa refills Reigen's coffee mug, worrying his bottom lip all the while. =============================================================================== Reigen takes them out on a job the next day. He explains the benefits of walking over driving as they make their way downtown to an old warehouse, abandoned for a year, possibly haunted. Serizawa doesn't understand a lot of Reigen's arguments, but Mob listens closely to his every word, so he does the same. The warehouse, it turns out, is filled to the brim with garbage. Reigen heaves a sigh as they survey the scene, then makes a fast, complicated gesture with his hands. "We'll split up, take a look around. The ghost will probably turn out to be giant rats. Tell me if you sense something." And he's off into the maze of old furniture and household appliances, Mob heading in the opposite direction. Something creeps up Serizawa's back as they disappear from sight, a sense of forlornness he thought he left at his mother's house the day he woved to never return to his room. He's not used to being left to his own devices when it comes to work; Touichirou always had a vision, no matter how small the task. Reigen, Serizawa realizes as his heartrate picks up, might be stitched from a different material. His hands shake as Serizawa lifts them to grab onto his forearms, holds himself steady as his lungs suddenly heat up and every breath leaves a mild sting somewhere behind his ribs, fingernails digging into the fabric of his suit, and he really wishes he still had his umbrella right now, something to help protect himself from the rising nausea. "Serizawa," he hears from nearby, a voice so calm it raises goosebumps on the back of his neck. He whips his head around, legs twitching to make a run for it as Mob watches him from around a corner. "You can come with me if you don't know where to look. Master Reigen can be a bit unspecific at times." He waits patiently as Serizawa swallows the lump in his throat, slowly releases the grip on his arms. His heart still racing and his breathing still ragged he takes a few steps towards Mob, who turns around and watches over his shoulder for him to follow. "There are two paths here," the boy explains. "We can split up to save time." "Where do you want me to look?" Serizawa's voice breaks on the last syllable, but he manages to supress a flinch. Mob turns his head to the left, to the right, and back to Serizawa. "You can take the right," he says, "and I'll be over here. You can tell me if you find anything, and then we can let Master Reigen now." The tone of voice doesn't quite fit, but the familiarity of being given orders pushes Serizawa back into his comfort zone, lets him breathe again. He gives a slight nod, shakes out his hands, and Mob rewards him with a friendly smile. Something inside of him unfurls itself as Serizawa heads to the right, pushing aside memories of tall men with dashing smiles and bright blue eyes. =============================================================================== Mob holds out his hand one time, picks Serizawa up from the ground after he tripped; the feeling of warm skin and careful, soft fingers wrapping around his own haunts Serizawa for days, keeps him up at night as he touches himself. =============================================================================== Reigen rarely passes out direct orders. He spends a lot of time at his desk taking all kinds of notes, sometimes in neatly kept notebooks, sometimes on napkins. He sits with his feet up on the desktop a lot whenever he thinks nobody's watching. Serizawa spends a lot of his time cleaning. He prefers to keep his hands occupied, so he doesn't mind, but Reigen's office is on the small side and kept in surprisingly neat condition already. The soles of his feet start brimming on days when they don't to much, a reminder that work should be spent working. His eyes keep twitching in Mob's direction, occupying himself with homework at the coffee table, but every time Serizawa contemplates sitting down with him his feet refuse to move. Reigen eventually excuses himself for 'business related stuff, I'll be back in half an hour,' and the door falling shut rings through Serizawa's head like a gunshot. "Ah. Master is going to smoke." Mob lets loose a tiny sigh, then focuses back on his schoolwork. Seconds tick by loudly on the wall clock, paired with the light scratching sound of Mob's pen, and finally Serizawa wills his body to approach the boy, even as his knees wobble with every step. He sits down on the opposite end of the sofa, wipes his damp palms on his slacks. He can feel Mob's gaze on the side of his face and takes a deep breath before he turns to meet it. The wall clock ticks, ticks, ticks before Mob asks, "Are you okay, Serizawa? You're sweating." He doesn't remember the last time he felt okay after leaving Touichirou; maybe he didn't feel okay even then. Mob leans back in his seat as Serizawa breaks eye contact, shifts his view towards the kid's hand resting limply beside his thigh now. He slides his own hand across the space left between them, grabs onto Mob's with shaky fingers, gives it a light squeeze. It's just as comforting as he remembered, just as warm and soft as he recalled it being many a night spent awake in his too large bed, too quiet flat. Those short, slender fingers twitch lightly for a fracture of a second, but they never draw away. "Tell me if I'm overstepping any boundaries," Serizawa says, remembering the times he got too friendly with Touichirou. They're so unalike yet similar in every way, and for a second Serizawa almost hopes for Mob to blast him back with a burst of his powers. Instead he squeezes back with vigor, and when Serizawa chances a quick glimpse at his face, he's smiling. "You're my friend," Mob says, "So this is okay. I hold hands with my brother sometimes." Serizawa wonders whether said brother's hands feel just as soft as he strokes Mob's with his thumb, revels in the fact that he's allowed to do so. But the boy tugs on his arm lightly, says, "You can come closer if you want," and Serizawa's eyes shoot open wide. He knows that phrase. It sends a lukewarm shiver through his body that settles somewhere between his ribs and abdomen, and when Serizawa lifts his eyes he almost expects to see the red-haired boy with the piercing blue eyes sitting there instead, smirking with his hand too close to his own crotch, telling him about how father won't be home for the day, about the offer of a wet tongue and a young, slender body. But the hand he's holding onto still belongs to Mob, with his black hair and deep brown eyes, his lithe torso, lither limbs. It's too tempting a prospect, and Serizawa slides closer to him without a second thought to consequences. They're thigh to thigh, entwined hands resting on their legs. Mob leans back a fracture of an inch to look up at Serizawa, searches his eyes for something. His mouth is slightly open, pale pink lips parted to reveal a hint of white teeth. He blinks, eyes slightly lidded, showing off surprisingly long lashes for such a young boy. Serizawa brings his other hand up slowly to hold Mob's face, cups his smooth cheek, and the gentle warmth spreading through his palm stops his fingers from trembling. For the first time since taking this job, Serizawa feels at peace. But Mob shies away from the touch, shifts his head to the side to put space between them, eyebrows twitching quizically underneath his bangs. "What are you doing, Serizawa?" he asks, voice soft and confused. They're still holding hands, so Serizawa gives him a squeeze. He's familiar with games like this, too – playing 'hard to get' was what Shou liked to call it, one hand down Serizawa's pants, the other holding his mouth shut as he talked about all the things his father might do were he to know his lackey had touched the boy without permission. So Serizawa says, "I'm getting closer," as he gently strokes Mob's cheek with his knuckles, brushes away a few strands of hair with his fingertips . Mob keeps his eyes fixed on Serizawa's face as he leans into the touch ever so slightly, lets one finger trace the line of his jaw and another the curve of his lips. His thumb and index finger are steady as Serizawa holds Mob's chin in them and pulls the kid in for a first, tentative kiss. It's light and sweet, almost chaste in a way Serizawa hasn't experienced before. The urge to spread Mob's mouth wide open dwindles as the boy pulls away after a few short seconds, squeezes the hand that's so much bigger than his own. He leans their foreheads together, noses touching, mouths not quite in reach of each other. It's entirely new but nice, and Serizawa feels content to indulge him for a moment longer. A metallic click finally makes him jolt, sends a panic through Serizawa's body that wraps itself around his chest, constricting every quick breath he takes as their heads whip around in unison. Reigen is standing at the door, hands in his pockets. He looks too casual, too calm, and Serizawa braces himself for a fight, for a painful lesson in decency about when and where and how to touch what doesn't belong to him. But Reigen lazily nods his head at the windows. "You left the blinds open," he says, and strolls over to shut the first one. "This is a ground floor office. A random passerby could have seen you guys and called the police." He shuts the second set of blinds, and the room instantly becomes a lot dimmer. Serizawa feels frozen in place, one hand still holding Mob's, the other hovering beside the boy's face – he quickly draws it back, clenches it in his suit jacket. Reigen rolls his office chair around the desk – he locks the door with a loud, harsh click on the way – and places it across from the coffee table and sofa. When he takes a seat, Serizawa starts shaking again. "I–I'm sorry," he tries, feeling so small all of a sudden. "I, th–this is not what it looks like, I promise. I would never – I'd never, I –" Reigen clears his throat, crosses one leg over his knee as he leans back in his chair. "I don't know what you're apologizing for," he says, "but I think you guys were in the middle of something. Please," he extends a hand towards them, "feel free to finish. It'd be rude of me to interrupt." The rest of Serizawa's explanation dies somewhere between his vocal cords and windpipe ("I'd never touch what's yours without your explicit permission") as he recognizes this as Reigen's way of passing out orders – indirect and unspecific, yet leaving no room for argument. This time, Mob is the one to reach out first, careful fingers turning them face to face by Serizawa's jaw, mouth on his own before he can try and read the boy's reaction. They're less careful now, Mob holding them pressed together, but still moving his mouth too gently for it to feel right. It's never been this way, never been tender and slow, and it puts Serizawa on edge to feel so lost in a situation he's so used to. Mob gasps as his lips are forced open, reflexively bites down on the tongue being shoved in his mouth and the pain surges through Serizawa's body, makes him shudder as he grabs Mob by the hips and pulls him closer, letting go of his hand for the first time in what feels like forever. The kid can't quite match his pace, his movements, but Serizawa delights in the way he gives it his all, how small his mouth feels fitted against his own, how tiny his waist seems under broad hands; he supresses the urge to knead the soft form into a bruised mess, doesn't crush it even when his hands twitch to do so. Mob slings both his arms around Serizawa's neck, lifts himself off of the sofa to try and match their height, hands scrambling across his back, trying and failing to find purchase in the smooth material of his suit. They're both still dressed, still decent, so Serizawa brings his hands up to Mob's uniform jacket and pop, pop, pops the buttons without hesitation (Shou's jacket had buttons just like these), runs his palms up Mob's chest to his shoulders and pushes him back down to slide it off, never letting go of that thin, narrow mouth. But Mob still has a shirt on, smooth cotton that Serizawa fists his hands into, and he has to break the kiss to lift it over his head, toss it aside blindly. He takes a moment to take in what he has exposed: Mob is smooth in every way, from his shoulders to his hips and tummy, no marks on his skin, no stories there to tell. Serizawa grabs his head with both hands, crushes their mouths back together, but Mob shoves at his chest and immediately slides his hands underneath the suit jacket as Serizawa lets go of him. They work it off together, and Mob's fingers shoot down to the buttons on the white dress shirt, bypass the tie, and Serizawa's cock gives a violent twitch in his pants. Mob untucks the shirt with nimble fingers, puts his open palms on Serizawa's stomach who swallows down a sudden bolt of insecurity about the hairy, flabby mess he must appear compared to Mob's flawless skin. He turns his head to the side to avoid any judgmental looks as they work his shirt off, and from the corner of his eyes he catches a glimpse of Reigen stroking himself through his pants with one hand, the other holding his chin in a thoughtful position, elbow on the armrest of his chair. But Serizawa is familiar with taunts and insults, and he runs his hands down Mob's arms to his wrists, holds them both in one hand and goes back in for another kiss. They're getting sloppier, less technique and more raw need as Mob carefully digs his teeth into Serizawa's bottom lip, pulls on it lightly, and he can't keep the sounds in anymore as he kisses the boy even harder, deeper, and his moans vibrate through both their bodies. Mob is trembling beneath his hands, goosebumps on his skin as one palm slides up his ribcage, careful to catch every ridge on its way upwards. Mob tries to tug his hands free but Serizawa's hold doesn't give, doesn't budge, as he slides his palm back down again, opens the boy's leather belt with trained ease. He puts his hand on Mob's thigh for now, draws his head back to give them both a moment to process the situation. "Mob," they turn their heads in Reigen's direction. "Why don't you get down on your knees for Serizawa?" Reigen's voice is slightly strained now, one hand working his cock through the open button fly of his slacks, the other hand still holding his chin in a thoughtful pose. Serizawa is still distracted when Mob frees his wrists and drops to his knees eagerly, spreads Serizawa's legs apart and wedges himself in between them. He looks up, and their eyes meet as his hands work belt and buttons free, fingers trembling with either nerves or anticipation. He looks so short down on the floor like this, but one hand boldly slides into Serizawa's boxers, and he helps the kid by tugging down his pants to give him better access. Mob takes a moment to look at the cock in his hand, traces his thumb up a vein before he gives the head a small stroke and the shaft a few pumps. Serizawa squeezes his eyes shut and takes a few shuddering breaths (it's too tender, too tender, this kid is going to kill him) but he gasps when Mob's mouth suddenly engulfs him, and so does Reigen from across the room. Mob can't fit much in his mouth – he barely gets past the head before he starts choking – but the way his tongue moves, the precision with which he finds the right spots to caress with his tongue and hand tells Serizawa he's done this before. Reigen draws a hissing breath when Mob brings up his other hand to stroke Serizawa's balls with, and he knows exactly who taught the kid. He finally opens his eyes once he grows accustomed to the sensations, watches Mob work diligently, head bobbing lightly in his lap, hair compelling him to run a careful hand through it with the way it sways. Serizawa knows he's close but he's learned to restrain himself, has learned to fuck and cum on command, and he wants to enjoy a sight he's never been allowed to just watch before. He runs his hand down to the back of Mob's head – not forcing, merely guiding – keeping his touch light as that tongue swirls around his head again, licks up salty precum, and the tiniest sound escapes the boy's throat, vibrates through Serizawa's body to make him choke out a moan, and when Mob suddenly opens his eyes and looks up at him, swallows down as much as he can fit, it finally becomes too much to bear. Serizawa digs his other hand into his own thigh, tries to numb the ecstasy with the pain of short, blunt nails biting into flesh, but it drives his high even higher, and he's coming in Mob's mouth with a groan and a snap of his hips. But Mob draws his head back in shock, coughs as cum runs down his chin and Serizawa coats his nose, his cheeks, his hair, leaves his pretty young face a mess. Reigen is panting somewhere in the background, chair creaking with the strain of his movements, but Serizawa keeps his gaze on Mob, on those big eyes looking down at the hand he used to wipe excess cum from his chin with. He lifts his face a moment later and keeps eye contact with Serizawa as he brings the hand up, pops a stained finger in his mouth with a wet plop, and in that moment the world really must have stopped turning in the face of a sight so extraordinary. "You're beautiful," he tells the boy, voice amazed but steady, and a shaking moan tells him that Reigen cums at the words. Serizawa pets Mob's hair, falls in love with the way he rubs his face into that broad hand, the way his chest expands in a long, contented breath. The kid draws his hand back from Serizawa's body, lets go of his soft dick without tucking him back in. "Mob," and they turn their heads again, slower this time. "Mob, get up on Serizawa's lap, or come over here," Reigen says, sitting slumped in his chair, hands stapled in front of his face, pants already buttoned up again. He would look calm and collected if it weren't for the sweat on his brow and the cum on his shirt and jacket. But Mob's face grows hot under Serizawa's hand, and he shifts around uncomfortably. "It's alright, Master," he whispers, "I'm already done." Reigen closes his eyes and inhales deeply, then gulps and nods his head. "Alright," he says, "Alright. Get dressed, you two. It's after closing hours, I don't want you doing overtime." And Mob disengages himself from Serizawa's hand as he gets up to gather his clothes, and Serizawa misses his warmth as soon as it's gone, looks down at his palm wondering if he will get to feel it again. They dress themselves quietly, but when Mob passes by him on his way out he shoots Serizawa a tiny smile, wipes a paper towel across Serizawa's sweaty forehead in a gesture so sweet it nearly makes his eyes water. It's the same old, same old, and yet it's so new and different that Serizawa leaves the office with his head spinning, mind unable to connect what's familiar to the new and foreign experiences he made today, unsure which outweigh which. =============================================================================== Serizawa doesn't sleep that night, recalling the sound of Mob's voice and the way his body moved with so much young grace, unlike the erratic, needy undulances he was so used to for so long. Maybe, he thinks as he traces patterns on the ceiling with his eyes, this is what Touichirou was aiming for when he told him he'd 'teach him how to love a boy'. End Notes Please feel free to point out any mistakes, English isn't my first language and I'd love to improve! Also feel free to drop by my twitter @hentaijohnson anytime! Please drop_by_the_archive_and_comment to let the author know if you enjoyed their work!