Urine Mineral Water (1)
I returned home still trapped in a haze of utter confusion.
‘She has a boyfriend, yet she still asked me to practice again… What the hell is she thinking…?’
Maybe she had some kind of complaint about her boyfriend? Or was she seriously just using me as a test subject for her first real experience?
Haemin had always been the quiet type with almost no change in expression, making it impossible to read what she was really thinking.
‘...This is my first time feeling it.’
The words she had whispered right after climaxing from my stimulation of her G-spot refused to leave my head.
The sharp, lewd scent of her pussy still clung stubbornly to my fingers.
I secretly brought them to my nose and sniffed, only to jump in shock when my little sister in her pajamas suddenly slammed the door open. I quickly hid my hand behind my back.
“Oppa! I need to wash up and sleep soon, so take your dick out!”
“U-ugh…”
I had thought the day was finally over, but with only an hour left until midnight, my sister had decided to wash up early and go to bed.
In the end, I ended up receiving another blowjob from her before sleep.
*Slurp… slurp…? Suck… slurp… slurp…*
“Khh… Ah, aah… Ooooh… Ah… Ngh!”
My sister’s small mouth made her cheeks puff out adorably like a hamster’s whenever my cock slid inside.
When I groaned like a pervert and grabbed her hair, she shot me a sulky glare and began thrusting my dick deep into her throat, pulling it out, then pushing it back in repeatedly.
“Aaagh…!! Ah, aah…!! I’m cumming…!!”
The moment she sensed I was about to ejaculate, my sister bobbed her head back and forth with ferocious intensity, sucking me in.
In the end, I pumped the last thick load of the day straight into her mouth.
Even while I was cumming, she kept her lips wrapped tightly around my shaft, scooping every drop from the corners of her mouth. At the very end, she swished the pool of semen around like mouthwash before swallowing it with a loud gulp.
Finally finished brushing her teeth, my sister wiped her mouth with the back of her hand, glanced at me sideways, and grumbled.
“...Oppa. The amount is a bit less than in the morning?”
“U-uh… yeah… Everyone at the cram school kept asking for it, so…”
I broke out in a cold sweat and mumbled awkwardly. My sister frowned in clear displeasure, crossed her arms, and said,
“...Other girls asked you for it? Why?”
“W-well… I’m the only guy left in the class… so it can’t really be helped…”
I barely managed to swallow the urge to add, *I have no idea why it turned out this way.*
She shot me another dissatisfied glare and snapped coldly.
“...Ugh, that’s annoying. Get lost and die, oppa.”
With that, my sister spun on her heel and stormed off to her own room.
The moment she was gone, I collapsed onto the bed in total exhaustion.
‘...She acts like she hates me so much, but she’s always been insanely jealous whenever I’m with another girl… What the hell is her problem…?’
I shook my head helplessly, curled up, and drifted off into a hazy sleep.
I wasn’t usually the type to fall asleep this quickly, but after being milked to my absolute limit day after day, both my body and mind were completely drained.
I fell into a deep, almost comatose sleep, not moving even a single centimeter.
But right in the middle of that dreamless slumber—
Someone grabbed my shoulder and shook me. I forced my heavy eyelids open.
In the dim room, my sister stood right in front of me wearing loose pajamas, looking extremely sleepy.
“...Huh…? Seoa…? Why are you in oppa’s room…?”
I lifted my head in confusion and asked.
Still half-asleep, she mumbled in a groggy voice.
“Oppa… I’m thirsty… Give me water…”
I tilted my head, puzzled.
“Huh…? If you’re thirsty, just go drink from the water dispenser. Why wake me up…”
I let out a dry laugh, thinking she might be scared to go into the dark living room alone like when she was little.
If that really was the reason, it was cute enough that I could forgive being woken up in the middle of the night.
But instead, my sister made an irritated face and snapped at me.
“What are you talking about, idiot… If it’s not from you, where else am I supposed to get water…”
“Huh…? W-what…?”
I was staring at her in utter bewilderment when a single possibility suddenly flashed through my mind.
‘N-no way… Is this the Common Sense Alteration that changed at midnight…? Then when she’s asking for water, does she mean…?’
Sure enough, right after that thought, my sister demanded in an annoyed tone,
“Oppa, give me your piss! Piss! I’m so thirsty I can’t sleep!”
“P-piss…? N-no, but…”
“Ugh… So annoying in the middle of the night…”
Without waiting for the frozen, panicked me to respond, she yanked my pants down, pulled out my already rock-hard cock, and knelt.
Then she aimed the tip at her open mouth and said,
“...Okay. Open wide so I can drink. Hurry up and piss.”
“U-ugh… W-wait a second…”
My mind was already foggy from being woken up, and this bizarre nightmare-like situation made my head spin even worse.
Up until now it had only been semen—either eaten or rubbed on her.
Of course semen was plenty perverted, but at least it wasn’t *dirty*.
Couples often swallowed each other’s cum, and it wasn’t strange for it to go inside the body.
But piss was completely different. Anyone could see it was blatantly unsanitary—something that should never be mistaken for a drink.
…Still, what could I do? This Common Sense Alteration clearly made people mistake urine for water.
Even so, I couldn’t bring myself to make my one and only little sister drink my piss. I struggled desperately to resist.
“S-stop it…! That’s not water, it’s piss! Piss! It’s dirty urine!”
“What are you even saying? I know it’s piss. So what? Just give it to me already! I have to wake up early tomorrow, so I need to sleep!”
No matter how much I thrashed and tried to push her away, my sister ignored me completely and finally took my cock into her mouth.
Frowning, she tugged at my pajama top as if urging me to piss quickly.
“H-hngh… Khh… Ngh…”
I had drunk a lot of water before bed, so I really did need to go badly. But the guilt was overwhelming. I simply couldn’t piss in my own sister’s mouth.
This was the kind of hardcore, extreme play you’d only see in the most depraved Western porn.
Honestly, the taboo thrill made my head spin with arousal. I wanted to unleash a powerful stream right then and there. But as long as I was still human and not a complete beast, I had to hold back.
What kind of older brother would piss in his little sister’s mouth? Who the hell could do something so demonic?
“Mmph! Mmph! Mmmph!”
But my sister, unaware of my inner turmoil, kept my cock in her mouth and tugged insistently at my clothes, demanding I hurry.
I was completely helpless, sweating buckets with no idea what to do.
The most vicious part of this Common Sense Alteration was that, unlike before when I had been forcibly milked, this time it required my own active consent. It couldn’t happen without my willing participation.
Forcing someone to piss was practically impossible. In other words, I had to consciously decide to piss in my sister’s mouth…
As I stood there frozen, eyes squeezed shut in panic, my sister finally reached the limit of her patience and used her last resort.
With an angry expression, she slammed her fist as hard as she could into my lower belly, right where my bladder was.
“A-aah…! No…!!”
The uncontrollable pressure made a few drops of piss leak into her mouth.
Of course I immediately clenched with all my strength to stop it, but she had already swallowed the drops I’d released with audible gulps.
Then, as if it still wasn’t enough, she opened her mouth wide again and teasingly tapped the tip of my cock with her tongue.
“Ugh… Haa… Hng…”
The look on her face was so lewd and immoral that I could barely stand it.
I fought desperately against my desire until the very end, but eventually my reason completely collapsed.
The moment I relaxed even a little, a powerful, unstoppable torrent of piss gushed out like a broken dam.
My sister closed her eyes, kept her mouth open, and accepted every drop of my urine.
*Shaaaaa… ziiiip… zip.*
…By the time I finished, her mouth was completely full of my yellow piss, sloshing gently.
“Aah… Ah… Ha…”
Overwhelmed by an intense mixture of taboo guilt and a twisted sense of conquest, I staggered backward.
But my sister paid me no mind. She swallowed my piss in several loud gulps, then casually wiped her mouth with her pajama sleeve.
Still sounding half-asleep, she grumbled as she left my room.
“Tsk, now I’m wide awake because of you, oppa… Useless brother as always.”
I stared blankly at her retreating back, then finally hung my head in defeat.