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Kouhai’s Autumn
🕑 Added 2025-06-25 13:15:40 +0000 UTCDisclaimer: This story contains adult themes. It is not suitable for minors or the easily offended.
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Contains: Weight Gain, Stuffing
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Kouhai’s Autumn
“You two did good work last time, so the company is sending you to another out-of-town meeting.”
The businessman and his kouhai stood in front of their boss’s desk.
The woman vibrated with excitement. “We won’t let you down, Sir!”
The man’s eyes darted to her, and he couldn’t help but notice his coworker’s body jiggling in her suit. Returning his gaze forward, he saw the older man making a similar observation. His face betraying no emotion, the boss said, “I’m sure you won’t. We’re counting on you to make a… presentable showing to our new partners.”
“Yes, Sir!” They both said.
As they walked back to their desks, the man reflected on his boss’s particular choice of words. His kouhai’s suit skirt was nearly screaming at its seams. Her jacket flared over her hips, and the sole button closed across her torso left both her soft middle and abundant bosom on display in her tight white shirt. Instead of shedding the weight she’d gained over their holidays together, it seemed she’d spent the past months adding grams to that number.
She wriggled and almost danced as they crossed the office, humming happily and listing off all the things she planned to do on their trip. The man’s ears grew warm as he caught her wide rump swaying with each step, and he quickly averted his gaze. His kouhai’s ballooning body should have been a bad thing. They were office workers, not idols, but appearances and first impressions were very important in the high-stakes business world. Yet, as they reached their desks, and he saw her oppai quiver and heave as she slid her chair forward, bumping her keyboard and sending a cup of pens rattling, the man found himself pushing down inappropriate feelings for his junior coworker.
***
Rikei inhaled the warm steam as she stepped out of the shower area into the hot spring bath. The cool mountain air sent a shiver down her spine, and she shed her robe to step into the steaming pool. Before her toe touched the water, however, she noticed someone was already in the bath. A familiar brown-haired head rested against the wooden pool siding, eyes closed.
“Eh?”
Her friend’s blue eyes flicked open lazily, then widened in surprise. “What are you doing here?”
“I’m here for a symposium on molecular biology. What are you doing here?”
“The company sent Senpai and me here to meet with some new potential partners.”
So that man was here as well. When she first met him, Rikei had doubts about her friend’s senior coworker. They seemed to spend a lot of time together, perhaps too much time, and old habits are hard to break. When they were in college together, Rikei spent a lot of time protecting her friend from guys when she inevitably drank too much. But the more she got to know the man, the more she trusted him—he was as protective of her friend as she herself had been. Rikei couldn’t imagine that one ever taking advantage of her friend in a vulnerable state. Or any state, for that matter.
Rikei lowered herself into the steaming bath, sighing as the heat seeped into her aching muscles. As always, her breasts bobbed and floated in the water; it was one of the few times she got a break from their constant weight, and she luxuriated in the relief. Her friend’s eyes drifted closed again, and Rikei noted that the floating “islands” on the other woman’s chest were quite a bit larger than her own. Her friend had always been the more busty of the two of them, but she’d really ballooned over the past few months. Her scientific curiosity piqued, Rikei tried to calculate her friend’s current size. Based on the average density and buoyancy of body fat, water displacement, and the angle of the other woman’s posture, she estimated her friend’s bust measurement must be at least 110cm, possibly as much as 112cm. That meant she was wearing 70N bras. Just how big could those things get?
The office lady reached for a floating tray Rikei hadn’t noticed, pouring herself a cup of sake from a ceramic bottle. Even when relaxing in a hot spring, her friend was indulging herself.
“You want some?”
“Sure.”
Rikei sipped the alcohol. The cold sake somehow tasted even better against the water’s steamy embrace. “So, how’s the ASMR going?”
Her friend’s face lit up. “Oh! So well! I wore that Mai costume in my last one, and it’s got half a million likes last I checked.”
Rikei almost spat out her drink, imagining her friend’s massive boobs in the skimpy fighter’s garb. No wonder the video was doing well—she was lucky it didn’t get flagged or taken down.
“That’s great! Do you have any plans for the fall?”
“Well… one of my followers said there’s an Oktoberfest in the city. I was thinking of asking Senpai if he wants to go.”
“That does sound like fun. I might join you if you do.”
“Yay!”
“Oi, don’t splash!”
***
The man stood outside a costume rental stall, waiting for the ladies to finish changing. They’d tried to talk him into renting a costume as well, but he refused to rent more than a hat, dark brown with feathers in the band. He felt ridiculous even wearing that, but the way his kouhai smiled with delight when he put it on changed his mind.
Inside the changing room, Rikei was engaged in a heated battle with a set of wide cloth laces.
“Pull tighter!” Her friend wheezed.
“You’ve gotta suck in that gut if you want it any tighter,” Rikei growled.
“I don’t have a gut! Quit being so mean!”
A mousy little stall worker, who couldn’t have been more than twenty, wrung her hands as a single bead of sweat ran down her brow. “We have dirndl in other sizes, miss. Perhaps a double large?”
“I don’t need a double large,” the office lady gasped as if the girl had slapped her. “Large is bad enough. Just tighten it properly!”
The blouse and skirt fit fine. Both were loose enough to drape over the woman’s wide hips and bottom, though the blouse clung tightly to her larger bosom. Rikei wrapped a cord around each palm, crouching in the shadow of that bosom to pull with all her weight as her friend braced herself on a corner post of the curtained stall. Bit by bit, the laces drew the sides of the heavy bodice together, cinching her friend’s midsection nearly as small as it’d been a year ago.
“That’s –ha– enough… I have to breathe…”
Rikei wanted to snap at her friend to make up her mind, but she quickly tied the laces as best she could while keeping their tension. Stepping back to admire her handiwork, she couldn’t argue with the results. Her friend’s waist wasn’t as trim as it’d been when they were students, but neither was hers, though she’d never admit it. The constraining bodice ended just below her friend’s breasts, making their ridiculous size even more pronounced.
“There,” Rikei panted. “It’s on.”
“You look very nice, miss.”
The woman brushed her hands down the sides of the costume, turning to take in her reflection in a full-length mirror. Her cheeks pinked, and she tugged fruitlessly upward at the blouse.
“There’s a drawstring on that,” The girl suggested.
Rikei reached for the thin string, but her friend swatted her hands away. She plucked the strings herself, crossing them and pulling them away from her chest. The blouse drew tighter around her breasts, making the mounds of her cleavage bulge even higher, like twin lumps of bread dough rising toward her chin.
Rikei gasped, and the girl looked like she might faint. Rikei said, “M-maybe you better leave it open.”
The office lady dropped the strings, and her breasts settled back into the blouse, filling the soft cotton plumply. “Yeah, that’s just making it worse. Come on, Senpai is waiting for us. Plus, I’m starving, and I need beer.”
Rikei couldn’t wait to see the man’s face. I bet his eyes fall out of his head.
A lump the size of a tennis ball formed in the man’s throat when the two women emerged from the stall. The scientist looked quite handsome in the traditional Alpine garb, but his eyes were inevitably drawn to the figure of his kouhai. How was it possible that a simple costume could make her so much cuter? She was like an anime character with huge boobs and a tiny waist. She blushed as she caught him staring.
“H-how is it?”
The man couldn’t speak. He was terrified of saying something stupid, or at least wholly inappropriate for a senpai to say to his kouhai. He gave her a thumbs-up.
Her friend smirked. “I think you broke him.”
“Huh?”
“Never mind. Let’s go get some beer.”
“Yay, beer!”
Once he got a stein of beer in him, the man loosened up. He enjoyed hanging out with his kouhai and her friend, even if the glasses-wearing lady liked to tease him a little too much. For her part, his kouhai seemed mostly interested in trying every kind of German food available at the festival. Bratwurst, roast chicken, pork shanks they called schweinshaxe, spaetzle, schnitzel, and more kinds of pretzel dip than he’d ever seen. Each dish was accompanied by copious lager or ale, and the man started to worry about getting her home. He’d had to carry her on his back more than once after a night of celebrating a successful project. It hadn’t happened since before the holidays, though, and he was already getting embarrassed by how weak he’d look if he wasn’t able to lift her heavier body.
With as much as she was eating and drinking, the man thought he could see her getting heavier right before his eyes. Her costume was incredibly tight, but the white shirt around her bosom seemed to be getting tighter as the afternoon wore on.
At one point, her friend said, “Hey, don’t you think you should slow down a little?”
The woman spoke through a mouthful of schnitzel. “Hmm, why?”
“I’ve just… never seen you eat so much.”
“Pfft, we didn’t take three trains all the way to this side of town to not enjoy ourselves.”
The man shuddered at the thought of having to haul his drunk kouhai—filled with meat and carbs and beer—across three train connections to get her home.
Her friend leaned in to whisper in her ear, and the woman’s eyes went wide. The man thought he heard the word “appetite.”
“So what if it has?” She hissed.
“I’m just saying… You don’t want to make a scene.”
“Nobody’s paying attention to me; they’re all here just having a good time.”
“If you say so.”
“Whatever, I’m getting another pretzel. Anybody want one?”
The man shook his head. He’d already eaten more than usual.
“Maybe one more,” The woman’s friend said.
When his kouhai brought back two large pretzels, her friend pulled two bites’ worth off of hers before sliding the paper plate toward her. “I’m more full than I thought.”
The man wondered how concerned the glasses woman truly was about her friend’s eating habits, if she was pushing her uneaten snack on her. It was almost as if she was using reverse psychology to get his kouhai to eat more…
As the woman got increasingly intoxicated from the delicious beer, her snacking grew more frantic, more desperate. When the man lost count of how many dishes she’d purchased and devoured, her flushed face started to look a little green. She and her friend spoke in whispers, but they weren’t quiet enough for the man not to overhear bits and pieces.
“…eating…streams…” Her friend said.
“…not that fulllll…soooo tight…”
“You…lace it that tight!”
“Yeah, but…breeeeathe!”
His kouhai’s friend examined her costume, then began poking and prodding at the laces and material covering her midsection. The man quickly averted his gaze.
“…told you…burst…this thing!”
“Oi!…really happen?”
“…don’t…find out…”
“…gonna do?”
“…rips…pay for it…”
The woman’s stricken expression was enough for the man to know it was time to head home, even before her friend grinned and said, “I think we better head back, Senpai-kun.”
Back in the changing room, Rikei tugged the knot loose at the top of her friend’s apron bodice, watching in fascination as her friend’s middle swelled to fill its newfound space. The woman sighed in relief, her bloated stomach pressing against the still-laced bodice. Rikei poked at a bulge of skin oozing between the thick laces. “I’m surprised you could breathe when we got this thing on you, and that was before you gobbled up a whole festival’s worth of food.”
The woman swatted away her probing finger. “Stooooop…”
The same employee from earlier poked her head between the curtains. “Do you two need any hel… ehhh?” She stepped inside, gaping at the office lady’s stomach. It was packed with so much food that it stuck out almost as far as her impressive bosom. “I guess you really enjoyed the festival, eh, miss?”
The woman only groaned, swaying unsteadily on her feet.
“I think we will need some help, actually,” Rikei said. “This one’s useless when she’s like this.”
The girl gave a brief bow and helped Rikei get her friend out of the costume.
“It’s a good thing you wore stretchy clothes on the way here,” Rikei said. “You’d never get your office suit closed.”
“Bigger size…” Her friend mumbled.
Did she mean she bought new suits in a larger size? Rikei wondered what size that could be and what size bras her friend had to wear to support those growing boobs.
Fortunately, the man didn’t have to carry his kouhai home. But he did need her friend’s help—each of them under one arm—holding her upright all the way to her apartment.
***
The man didn’t make much space for personal time in his life. He had goals for his career that superseded nearly everything else, so his days were quite full. He did try, as much as he could, to keep a little balance in his life. He’d seen too many people in high-pressure Japanese culture experience one small failure and spiral into delinquency because they’d gotten so tightly wound. One of these concessions was going out drinking with his kouhai and other coworkers to celebrate or blow off the proverbial steam. The other was watching a bit of TV on the rare nights he wasn’t working late, in between dinner and going to bed. Lately, however, he found himself uninterested in watching anything that was available. The news was depressing, anime wasn’t his thing, and dramas were either too boring or too melodramatic. Most critically of all, nothing on TV could distract him from thinking about his kouhai. He’d had improper feelings toward her almost since her first day, but it had somehow gotten worse in the past year. At work, he could focus; he had tasks to occupy his mind. But alone in his apartment, his treacherous imagination replayed her large, bloated, jiggling, growing breasts on an unending loop.
So, he turned to the internet. YouTube had more content than he could ever watch, and he discovered soothing kinds of videos that were the perfect wind-down and release after his long days at his desk. He watched people build or refinish small pieces of furniture. He watched restoration videos with no talking. He even watched a few solo camping girls, though that often just reminded him of her all over again, shamelessly comparing the size of their assets.
The real game-changer was ASMR. He’d never understood it when people tried to explain it to him, but some magic combination of sights and sounds would sometimes send tingling down the nape of his neck, soothing away all his work stress and emotional angst. He could never tell when it would work. One hair-brushing video would give him tingles; the next would just annoy him. One shop roleplay would make him fall asleep in his chair; the next, he’d critique the script or acting. And forget about most mouth sounds. The licking and chewing and tongue clicking either simply disgusted him or reminded him yet again of his kouhai and just how much food she put away to keep growing those oppai larger and larger.
Scrolling past some of these, the man saw a thumbnail that looked strangely familiar. He clicked on the video, and his suspicions were immediately confirmed. The woman in the video had most of her face outside the frame, but he caught the occasional glimpse of a very familiar small mole under her right eye.
She was noisily eating karaage, smacking her lips and commenting on the flavors in a very bad whisper. She wore some kind of kunoichi garb that was far too revealing to be authentic; she must be cosplaying some anime or video game character. As she ate and talked, crumbs of crispy breading showered down onto her exposed cleavage. Before his mind could form any coherent thought, the man pictured those calories she was wolfing down affecting the woman’s body. She would get even more chubby; hips wider, bottom rounder, tummy softer, and especially her huge boobs getting bigger and bigger and bigger. He knew she’d already bought larger suits for the office at least once since the holidays.
The office…
This was his kouhai he was watching!
The man quickly closed the app. His empty apartment seemed to tilt as the room fell silent, nothing but the hum of the refrigerator and the occasional rumble of a passing car outside. His kouhai, his precious, naive, innocent kouhai…
What should he do? What could he do?
The man opened his laptop, pulling up some work files. His only chance for sleep tonight would be throwing himself into work until he was too exhausted to stay awake.
***
The office lady was just making the final edits on her most recent video when her doorbell rang. Her friend stood outside carrying a paper shopping bag.
“What are you doing here?”
“I found you a costume for the Halloween party!” Rikei said, stepping into the genkan and slipping off her shoes.
“Halloween party?”
“Didn’t I tell you? A bunch of the girls from school are throwing a big party. After all your cosplaying, we just have to go!”
“I don’t know…”
Rikei pushed past her and set the bag on the kotatsu. “What do you mean you don’t know?”
“I mean… this isn’t YouTube or Comiket. These are people we know! They’ll see how… big I’ve gotten.”
“Pfft, you always worry so much.” Rikei pulled a black wig from the bag, and the hair just kept coming.
“What is that?”
“It’s a wig. You’re gonna be Sadako.”
“S-Sadako?”
“You know, from Ringu.”
“I don’t think I’ve seen that…”
“It’s that horror movie about the girl who crawls out of the TV.”
“You know I don’t like scary movies.”
Rikei pulled a bundle of pale cloth from the bag and stepped up to the woman, sliding the wig onto her head. Hair hung down almost to the floor. “The best part is, the outfit is just this dress. It’s supposed to be baggy, so you’ll have no trouble fitting into it.”
She let the dress fall open, holding it up against her body. The woman couldn’t tell just from looking down at herself, but she could feel it draping over her breasts. Even when Rikei spread the shoulders of the dress, its material didn’t seem to reach wide enough. Her friend’s eyebrows rose, her eyes bulged.
“I guess you’ve been doing more mukbang videos than I thought,” Rikei said, jabbing a finger into one of her breasts. She found the indent where her breasts were starting to overflow the cups on her bra. “What is this, a 70M?”
“O-oi!” The woman swatted her friend’s hand away, muttering a response.
“Eh?”
“It’s… um… 75N…”
Rikei’s mouth fell open. “Amazing… switched to a sister size, eh?” She patted the sides of the woman’s bosom, making them wobble. “These must be like 115cms by now.”
“No! They’re barely one-fourteen… How are you doing that?”
“Doing what?”
“Guessing my sizes.”
Rikei shrugged. “I’m a scientist. Like, I bet you weigh—“
“Stop!” She absolutely did not want to hear her friend’s guess on that. The scale clicked over to 64kgs last week, and she’d been afraid to step on the rude device since.
“Well, it’s fine if the dress is a little tight.” Rikei gave her a wicked smirk. “So long as you don’t grow too much in the next month.”
Comments
Crackedup
A new favorite of yours! This is great
