Haruto Tanaka lived in a shoebox apartment on the fourth floor of a building that smelled faintly of curry and regret twenty-four hours a day. Rent was cheap because the elevator had been broken since he moved in two years ago, and the landlady claimed "renovations" were always scheduled for next month. He didn't mind the stairs. Climbing them gave him time to pretend he was getting exercise instead of just slowly dying inside.
It was a Thursday evening in late spring. The sun had already dipped behind the neighboring high-rises, turning his single room into a cave lit only by the blue-white glow of his ancient laptop. Finals were three weeks away, his part-time konbini job had cut his hours again, and the last of his instant ramen packets stared back at him accusingly from the cupboard.
He opened the mini-fridge.
Inside: half a lemon that had turned into a sad green fossil, a questionable yogurt cup he didn't remember buying, and one lonely carton of milk. The label read "Premium Hokkaido Fresh – Whole Milk" in cheerful red letters. Below that, in smaller print: Best Before: April 15.
Today was May 2.
Haruto sighed. "You're probably fine. People drank worse in the old days."
He shook the carton. It sloshed heavily—still mostly full. He popped the foil seal, poured what was left into his tallest glass (a faded Pokémon cup he'd stolen from his sister years ago), and stared at the creamy white liquid like it might offer life advice.
Then he chugged.
The first swallow was… normal. Cold. A little sweet. The second swallow hit different. Thicker. Almost syrupy. By the third, his tongue tingled. Not painfully—just a strange, pleasant buzz, like licking a nine-volt battery while someone whispered compliments in your ear.
He finished the glass in four long gulps and set it down with a satisfied ahh.
That was when the world glitched.
A translucent blue panel materialized directly in his field of vision, hovering at perfect reading distance, impossible to look away from.
**[MILK UPGRADE PROTOCOL – SYSTEM INITIALIZATION COMPLETE]**
**[User: Haruto Tanaka]**
**[Age: 20 | Occupation: Unremarkable College Student]**
**[Current Level: 1 – Novice Milker]**
**[Core Ability Unlocked: Drink to Grow]**
**[Passive Skill: Milk Aura (Lv.1) – Females within 5-meter radius experience mild dehydration + increased suggestibility toward the User. Effect strength scales with User's consumed volume.]**
**[First-Time Bonus: +100% Upgrade Potency on initial activation.]**
**[Shared Upgrade Mechanic: Any female who consumes User-touched milk receives proportional enhancements. Enhancements are permanent unless revoked by System Administrator (currently: None detected).]**
**[Warning: Overconsumption may result in… enthusiastic behavior.]**
Haruto blinked once. Twice.
"…What."
He waved his hand through the screen. It passed right through like it was made of augmented-reality cosplay. He pinched his cheek. Hard. It hurt.
"Okay. Hallucination. I'm hallucinating. Too much caffeine, not enough sleep, maybe that ramen was expired too—"
The apartment door slammed open without warning.
Aiko Hayashi stood in the doorway like she'd been summoned by dramatic irony.
She was wearing her usual post-jog outfit: black sports bra that had seen better days, neon-green running shorts that barely qualified as clothing, and white sneakers still dusted with sidewalk grime. Sweat glistened on her collarbones and the flat plane of her stomach. Her ponytail was coming loose, dark strands sticking to her flushed cheeks. She looked like she'd sprinted here from the park three blocks away.
"Haru! Emergency!" she panted. "My water bottle exploded in my bag and I'm literally dying of thirst. Your door was unlocked again—seriously, you're gonna get robbed one day—and I saw the fridge light on. Is that milk? Gimme!"
She didn't wait for permission.
Aiko crossed the room in four strides, snatched the carton from the counter where Haruto had left it, tilted it back, and drank like a woman who'd just crawled out of the desert.
Milk dribbled from the corner of her mouth. A white rivulet slid down her chin, over the curve of her throat, and disappeared into the deep valley between her breasts. The sports bra—already stretched tight from her B-cup days—suddenly looked like it was fighting for its life.
Haruto couldn't look away.
Aiko finished the carton in one long, continuous pull. She lowered it with a gasp, lips shiny, a thin mustache of cream on her upper lip.
Then she froze.
Her pupils dilated. Her breathing hitched—not from running anymore. Something else.
"H-Haru…" Her voice came out softer, huskier. "Why does my skin feel like it's… buzzing?"
The system pinged again, louder this time, like a notification chime designed by a sadist.
**[Target Acquired: Aiko Hayashi]**
**[Milk Consumption: 320 ml (High potency due to First-Time Bonus)]**
**[Applying Upgrades…]**
**[Breast Tissue Expansion: +180–220% projected growth | Complete in 30 seconds]**
**[Erogenous Zone Sensitivity: ×4.7 | Permanent]**
**[Lactation Trigger Threshold: Lowered by 85% | Active]**
**[Loyalty & Attachment: +140 (Harem Candidate – Tier S)]**
**[Libido Spike: Critical. Subject will seek immediate physical relief from User.]**
**[Milk Aura Feedback Loop Initialized: Subject now radiates secondary aura. Nearby females at risk of minor thirst activation.]**
Aiko's hands flew to her chest.
"Oh—oh god—"
Her breasts visibly swelled.
It wasn't cartoonish bounce physics. It was slow, deliberate, almost sensual. The sports bra groaned audibly as the fabric stretched. Her nipples—already stiff from the cold milk and sweat—poked insistently against the material, darkening the black cloth in twin wet spots. She cupped herself instinctively, trying to contain the growth, but her fingers sank into newly plush flesh.
Each breath made them rise and fall more dramatically. By the time the expansion finished, she'd gone from modest B-cups to heavy, round E-cups that looked ready to spill out at any second. The underband of the bra dug into her ribs, creating soft, overflowing cleavage that jiggled with every shaky inhale.
Aiko whimpered.
It wasn't a pained sound. It was needy. Desperate.
"Haru… everything feels… too much. My nipples—fuck—they're throbbing. Every time I breathe they rub and it's like… like lightning straight down—"
She squeezed her thighs together. A fresh shiver ran through her.
Haruto's mouth had gone dry. His brain was buffering.
"Aiko, I—uh—this is… there's this thing, this screen, it says—"
She didn't seem to hear him.
Instead she stepped forward—close enough that he could smell her: sweat, vanilla body spray, and now something sweeter. Milk? No—something primal. Pheromonal.
Her pupils were blown wide. She looked at him like he was the only source of water in the world.
"I need…" She licked her lips, tasting the last traces of cream. "I need you to touch me. Right now. Please."
Haruto's hands hovered uselessly in the air. "Wait—wait, this is crazy, we should figure out—"
Aiko grabbed his wrists and placed his palms directly on her swollen breasts.
The moment skin met skin (well, skin met stretched sports-bra fabric), she moaned—loud, shameless, head tipping back.
"Yes—fuck—yes, like that—"
Her nipples were rock-hard little points under his thumbs. Even through the cloth he could feel how engorged they'd become. When he instinctively brushed one, Aiko's knees buckled. She grabbed his shoulders to stay upright.
"Don't stop," she gasped. "Please don't stop. It hurts so good—Haru, I'm so wet already, I can feel it soaking through my shorts—"
Haruto's rational brain finally gave up and went offline.
He squeezed—gently at first, then harder when she arched into his touch with another broken moan. The weight of her new breasts filled his hands perfectly, soft and warm and impossibly full. Every time he kneaded, a tiny bead of milk appeared at the tip of her nipple, darkening the fabric further.
She was lactating.
Already.
The system hadn't lied.
Aiko's hands fumbled at his belt. "Off. Clothes. Now."
She yanked his shirt over his head before he could protest. Her mouth found his collarbone, then his neck, sucking hard enough to leave marks. When she reached his lips she kissed him like she was trying to crawl inside him—tongue hungry, teeth nipping, little desperate sounds spilling into his mouth.
Haruto stumbled backward until his calves hit the edge of his narrow bed. They went down together in a tangle of limbs and half-removed clothing.
Aiko straddled him, grinding down hard. The damp heat of her core pressed against his erection through their remaining layers. She rocked shamelessly, chasing friction, breasts swaying heavily with each movement.
"Look at them," she whispered, cupping herself and lifting them toward his face. "They're so big now… because of you. Because of your milk. Suck them. Please. I need it—"
Haruto didn't need to be asked twice.
He pulled the sports bra down, freeing her swollen tits. They bounced once, then settled—full, flushed, veins faintly visible under pale skin. Her areolas had darkened and spread slightly; nipples stood out like ripe berries, already leaking thin streams of sweet milk.
He latched onto one.
Aiko cried out—half sob, half ecstasy—as warm milk flooded his mouth. It tasted like vanilla and sex and something addictive he couldn't name. He sucked harder. She bucked against him, fingers tangling in his hair, holding him there.
"More—fuck—more—don't stop drinking me—"
Her hips rolled faster. The wet spot on her shorts grew. Haruto could feel her clit swollen and pulsing even through the fabric.
When he switched to the other nipple she came—sudden, violent, thighs clamping around his waist as she shuddered through it. Milk sprayed in tiny arcs. She sobbed his name over and over.
But she didn't stop moving.
"Inside," she begged. "Need you inside. Now. Please, Haru—I can't wait anymore—"
They fumbled the rest of their clothes off in a frantic blur.
When he finally pushed into her, she was scalding hot, slick beyond belief, walls fluttering like they were trying to pull him deeper. Aiko threw her head back and keened.
"Yes—yes—fuck—so full—keep going—"
He thrust up into her, hands gripping her ass, guiding her rhythm. Every bounce made her breasts slap against his chest, milk smearing between them, slippery and obscene.
She came again—harder this time—nails raking down his back, chanting his name like a prayer.
Haruto followed seconds later, spilling inside her with a groan that felt like it came from his soul.
They collapsed together, panting, sticky, covered in sweat and milk and each other.
For a long moment, neither spoke.
Then the system chimed once more—soft, almost smug.
**[Milking Session Complete]**
**[User Level Up: Level 2 – Apprentice Milker]**
**[New Passive: Enhanced Recovery – Post-session stamina restored 300% faster]**
**[Aiko Hayashi – Status: Bonded (Tier S). Craves daily milk intake. Loyalty locked.]**
**[Secondary Aura Detected: Nearby females now experience +15% thirst probability.]**
Aiko lifted her head from his chest. Her eyes were still glassy, but a lazy, satisfied smile curved her lips.
"So…" she murmured, tracing lazy circles on his skin with one finger. "You gonna tell me what the fuck just happened? Or should we just… do it again?"
Haruto stared at the ceiling.
The empty milk carton lay on the floor like innocent evidence.
He had a feeling this was only the beginning.
To be continued in Chapter 2: Double Shot
(End of Chapter 1)