The buzzer rang again—longer this time, insistent. Then came the muffled sound of multiple voices in the hallway, overlapping in confusion and curiosity.
Haruto sat up so fast the bed creaked in protest. Aiko, still straddling Yuna's thighs, froze mid-lick. Reiko pulled a sheet over her chest like it might somehow restore dignity to the situation.
Yuna blinked up at the ceiling, cheeks flushed, milk still beading on her nipples. "Is… is that the delivery guy? I ordered takeout earlier…"
"It's not the delivery guy," Haruto said through gritted teeth. The system screen was practically vibrating with red alerts now.
**[Critical Alert: Multiple unbonded females detected within aura radius (15 m).]**
**[Thirst probability cluster: 82–97%.]**
**[Contamination vector: Airborne residue + vocal emissions from prior sessions.]**
**[Recommended action: Immediate containment OR accelerated bonding. Risk of public exposure: Severe.]**
Another knock—sharper. Then a familiar voice cut through the door.
"Tanaka! Open up! It's Mika from 402. I can hear… stuff. And it smells like someone dumped a dairy farm in there. What the hell is going on?"
Mika. Twenty-one. Third-year business major. Loud, confident, captain of the university women's volleyball team. Six-foot-one in bare feet, built like she could bench-press Haruto and still have energy left to tease him about it. She lived across the hall with her roommate—
The door rattled again.
"And Rin too!" came a softer, melodic follow-up. "We were studying and… um… the smell drifted under our door. It's… distracting."
Rin. Nineteen. Second-year literature major. Petite, long silver-dyed hair, always wore oversized sweaters that swallowed her frame. Quiet, observant, the kind of girl who noticed everything and said almost nothing.
Haruto pinched the bridge of his nose. "We are so fucked."
Aiko slid off Yuna, already reaching for the doorknob. "Not yet we're not. But we will be if we don't let them in before they start banging loud enough to get the whole building involved."
Reiko clutched the sheet tighter. "This is my building. I should… I should handle this professionally."
Yuna sat up slowly, hugging her knees, breasts still leaking tiny streams down her stomach. "I… I can hide in the bathroom?"
"No one's hiding," Aiko declared. "We're past that. Aura's too strong now. They're already primed. Let's just… speedrun the inevitable."
Before Haruto could protest, Aiko yanked the door open.
Mika stood front and center—volleyball practice jersey stretched tight across her broad shoulders and athletic chest, black spandex shorts hugging powerful thighs, hair pulled into a high ponytail still damp from a recent shower. Behind her loomed Rin, half-hidden, clutching a thick paperback to her chest like a shield. Both women froze when they saw the scene inside.
Mika's eyes widened, sweeping over the bed: Haruto half-naked, Reiko draped in a sheet, Yuna curled naked and glistening, Aiko standing proud in nothing but Haruto's oversized T-shirt.
Then she sniffed the air—deeply.
"Holy shit," Mika breathed. "That's not normal milk."
Rin's cheeks went scarlet. She didn't speak, but her gaze darted to the leaking breasts on display, then to Haruto, then back again. She bit her lip hard enough to leave a mark.
The system pinged like fireworks.
**[Cluster Exposure Confirmed]**
**[Targets: Fujimoto Mika | Level: High athletic baseline | Thirst: 91%]**
**[Targets: Aizawa Rin | Level: Low physical resistance | Thirst: 96% (amplified by observational sensitivity)]**
**[Ambient milk residue triggering passive craving cascade. Direct consumption imminent.]**
Mika stepped inside without invitation, kicking the door shut behind her. Rin followed like she was tethered.
"Okay," Mika said, voice low and rough. "Explain. Fast. Before I lose what little self-control I have left."
Aiko crossed her arms under her breasts, making them jiggle deliberately. "Short version? Haru drank some weird milk. Got a system. Now anyone who tastes his milk—or milk he's touched—gets upgraded. Bigger tits, crazy sensitivity, permanent horniness, loyalty thing. We're all… bonded now."
Mika stared. Then laughed—short, disbelieving. "Bullshit."
Rin whispered, "It's not bullshit. Look at them. Look at Yuna-chan's… they weren't like that yesterday."
Mika's eyes flicked to Yuna's swollen, leaking chest. Then to Reiko's. Then to Aiko's.
She swallowed. "Prove it."
Aiko didn't hesitate. She walked to the mini-fridge, opened it, pulled out the last unopened carton of the same brand Haruto had started with—plain white, no label frills—and cracked it open. She poured a generous splash into a clean glass and held it out to Mika.
"One sip. See what happens."
Mika hesitated—then took the glass. She brought it to her lips, inhaled the scent first, eyes fluttering.
Then she drank.
One long swallow. Then another. Then she drained it.
The change was immediate.
Her jersey tightened across her chest. The fabric groaned as her already impressive C-cups pushed outward—rounding, lifting, straining the seams until the neckline dipped dangerously low. Her nipples hardened into visible peaks, tenting the material. A wet spot bloomed over each one almost instantly.
Mika gasped, dropping the empty glass. It rolled across the floor.
"Fuck… fuck, that's intense…"
She cupped herself—then moaned when her thumbs brushed her nipples. Milk seeped through the jersey in thin streams.
Rin watched, transfixed. Her own sweater was starting to tent—smaller growth, but unmistakable. She whimpered softly, thighs pressing together.
Aiko took Rin's hand and guided her to the bed. "Sit. It'll feel better if you let it happen."
Rin obeyed, knees weak.
Mika staggered forward, eyes glassy. "I need… I need to…"
Haruto stood. He didn't know what to say, so he didn't say anything. He just reached out.
Mika grabbed his wrist and pulled him close—then kissed him. Hard. Hungry. Her tongue tasted like milk and mint gum. When she broke away, she was panting.
"Bed. Now."
The room dissolved into motion.
Mika stripped her jersey off in one fluid motion—revealing a sports bra that was already soaked and useless. Her breasts bounced free—now full, heavy DDs with dark, leaking nipples. She shoved Haruto back onto the mattress and straddled his hips.
Rin was pulled down beside them by Aiko and Reiko. Yuna, recovered enough to move, crawled over to help.
Clothes vanished in a frenzy.
Mika ground against Haruto's erection through his boxers, soaking the fabric with her own wetness. "You did this to us," she growled. "Fix it."
Haruto yanked his boxers down. Mika didn't wait—she lined him up and sank down in one smooth, powerful motion.
They both groaned.
She was tight, hot, athletic muscle gripping him like a vice. She rode him hard—hips snapping, breasts bouncing wildly, milk spraying in rhythmic arcs with every downward thrust.
Rin watched, mesmerized, until Aiko guided her mouth to one of Mika's leaking nipples. Rin latched on instinctively—sucking, swallowing, moaning around the flow.
Yuna and Reiko flanked Haruto—kissing his neck, his chest, hands roaming. Reiko fed him her own milk from her fingers while Yuna stroked his balls in slow circles.
Mika came first—back arching, cry echoing off the walls, walls pulsing around Haruto. Milk gushed from her breasts in twin streams; Rin drank greedily.
Haruto followed—spilling deep inside her with a guttural sound.
Mika slumped forward, breathing hard, but she didn't dismount. Instead she leaned down and kissed him again—slower this time.
"Fuck… that was…"
"Not over," Aiko said cheerfully.
She pulled Mika off gently and repositioned her on hands and knees. Then she guided Rin beneath Mika—so Rin's face was level with Mika's dripping core.
"Clean her up," Aiko instructed.
Rin obeyed—tongue tentative at first, then eager. Mika shuddered, pushing back against Rin's mouth.
Haruto, still hard thanks to the system's recovery passive, moved behind Rin. Aiko helped spread her—revealing pale skin, small but newly swollen breasts leaking onto the sheets, and a soaked, needy entrance.
He entered Rin slowly. She moaned into Mika's folds.
The chain reaction was immediate.
Mika ground back against Rin's tongue. Rin pushed back onto Haruto. Aiko knelt in front of Mika—offering her own leaking breasts. Mika latched on, sucking hard while Yuna and Reiko took turns kissing and touching everyone within reach.
The room became a symphony of wet sounds, muffled cries, the rhythmic slap of skin, the occasional splash of milk hitting fabric or flesh.
Mika came again—squirting onto Rin's face. Rin followed—clenching around Haruto, milking him until he spilled inside her too.
They collapsed in stages—bodies tangled, slick with sweat and milk, breathing ragged.
The system chimed—calm now, almost satisfied.
**[Cluster Bonding Session Complete]**
**[User Level Up: Level 5 – Master Milker]**
**[Harem Count: 5 / ?]**
**[New Bonds]**
**– Fujimoto Mika – Tier A+ (Athletic synergy detected)**
**– Aizawa Rin – Tier A (Observational imprint complete)**
**[New Skill Unlocked: Aura Dampening (Lv.1) – Temporarily reduce thirst radius by 50% for 6 hours. Cooldown: 24 hours.]**
**[Global Status: Contamination contained (barely). External attention probability: Stabilized at High.]**
**[Warning: Apartment complex now designated primary infection zone. Expansion risk increasing with each session.]**
Mika rolled onto her back, chest heaving, milk still trickling. "So… this is permanent?"
Aiko nodded, wiping her mouth. "Pretty much."
Rin curled against Haruto's side, whispering, "I… I don't mind."
Yuna giggled weakly. "Me neither."
Reiko sighed, maternal even now. "We need to talk about rules. And cleaning. And… food. We can't live on milk alone."
Mika snorted. "Speak for yourself."
Haruto stared at the ceiling—one last time for the night.
Five women. Five bonded, upgraded, obsessively devoted women.
And the fridge was empty.
Somewhere downstairs, the building manager's footsteps echoed—heading toward the stairs.
Haruto closed his eyes.
Tomorrow was going to be a very long day.
To be continued in Chapter 5: Supply Run
(End of Chapter 4)