The Line We Cross
My eyes felt like they were about to pop out of my skull. I’d been staring at my older sister’s body way too hard.
“Haa… haa… sniff… haa… haa…”
With trembling hands, Yunseo struggled to peel her t-shirt up. “Haa… haa… whew… huu…” Finally, with a rough exhale, she tossed the shirt she’d been wearing aside.
The only thing left protecting her breasts from her little brother’s filthy gaze was a single scrap of fabric. But sadly, ‘It’s white… so it’s a little see-through.’
The material was so thin and delicate it couldn’t even do its job properly. Her sharply protruding nipples proudly asserted their presence. Beads of cold sweat had pooled everywhere, especially soaking the underside of her breasts.
“Sniff… sniff… haa… haa… M-Minjun… can’t we stop here? I’m… I’m so embarrassed…”
Between her ragged breaths, little sobs kept slipping out. Large, glistening tears welled up in her eyes. Shame at showing her body to her brother, bewilderment, humiliation, disgrace—every possible emotion swirled across her face as she looked up at me like she couldn’t take any more.
“Sis. A promise is a promise.”
I pointed at her chest with my index finger.
“You still have one more to go.”
“P-please… haa… haa… just this much… or maybe wait five minutes—no, just one minute…”
“Kang Yunseo. Before I rip the rest off, hurry up.”
“T-then… you take one off too. I’ve already taken off one layer.”
“What kind of nonsense is that? You’re the one who agreed to go first.”
“Anyway, if you don’t take something off, I won’t either. You strip too.”
“……Fine.”
‘We already agreed to show each other everything. No point dragging this out.’
I did as she asked and slid my pajama pants down. My cock, which had been caught in the waistband, slowly sprang free. As a result, the front of my underwear jutted out obscenely.
“……”
Yunseo’s gaze naturally drifted down between my legs.
“Is that… cum? Or sweat?”
“Pre-cum. You know that much, right?”
“I’ve heard of it… but it comes out even if you don’t touch it?”
“When a ridiculously hot woman is sitting half-naked right in front of you.”
“O-oh… I see. So everything inside there is all your… that stuff, right?”
“What are you even saying? Speak clearly.”
“It just looks… really big. I thought maybe you stuffed something in there.”
“You’ll find out later anyway. Now it’s your turn. You have to finish taking it off, don’t you?”
“Ugh……”
“If you really can’t do it, I’ll take it off for you. But as you know, I’m a little crazy. I don’t know where I’ll stop.”
“Fine, I’ll take it off! I’ll take it off!”
Yunseo placed her hands on the hem of her camisole. But because of all the sweat, the fabric clung stickily to her skin and refused to budge. She twisted her body this way and that, fidgeting.
Maybe… she was deliberately stalling. Pretending it wouldn’t come off easily so she could keep her body hidden just a little longer.
In the end, the thirsty one had to dig the well himself. The moment her navel came into view—
“This is going to take all day at this rate.”
“Huh? Hey!”
I grabbed the camisole and yanked it straight up.
“!”
Jiggle.
Her full, perky breasts bounced free.
‘Holy shit……’
I knew her skin would be pale. I knew her nipples would be pink. I knew everything about her would be perfectly beautiful. But still……
Beads of sweat glistened on her chest like tiny jewels. Even the nectar of the gods that promised immortality couldn’t compare. I wanted to bury my face in them right now. I wanted to take them into my mouth, suck on them greedily, and savor their taste.
How sweet must she be? How delicious would this woman taste?
“W-what the hell are you doing? I said I’d take it off myself.”
“……”
Even though Yunseo snapped at me in anger, I couldn’t hear a single word. My entire mind was completely captured by her breasts. Only her breasts.
“……”
When I stared at her like I was trying to burn a hole through her, she finally shut her mouth too. Her slender neck, her delicate collarbones, her cute navel—everything about her drove me insane, but those plump, protruding nipples kept stealing my gaze the most.
‘She must feel the same way about this situation……’
“They’re such a pretty pink. Like strawberry milk.”
“……Thanks.”
“And they smell really good too.”
“You idiot. Don’t sniff me. You’re such a fucking pervert.”
“I said I wouldn’t touch. I never said anything about smelling.”
Sniff sniff. I leaned in close to her neck and flared my nostrils.
“How can you be this pretty? We have the same parents. How can you smell this good? How can you be this lovable?”
“You… you look decent too. Your behavior is trash, though.”
Her long black hair trembled as it fell across her chest. Pretending to brush it aside, I gathered a handful and gently brushed it across the tops of her breasts like a soft paintbrush.
“Hngh! Hey. Wait a second.”
“How can someone be this perfect? Seriously. It’s almost miraculous at this point.”
I paid special attention to her adorable nipples, as if dusting away invisible specks.
“Haa… Hey! Stop it! This feels weird! Haaang!”
With the brush made of her own hair, I poked and tickled her nipples. Eventually she covered her chest and backed away.
“What are you doing? Why are you covering up?”
“Y-you… we only agreed to look at my breasts, remember?”
“I haven’t touched your body once. That’s your own hair. You grew it.”
“Don’t make me laugh. You want to talk bullshit?”
“Anyway, you have to keep showing me. Stop covering up.”
“You fucking bastard. Just wait. I’m going to mess with you exactly the same way.”
‘Idiot.’
That would only benefit me.
“Why? Are they really wet?”
“You idiot. Stop asking weird questions.”
“Why? I’m like this because of you right now.”
Her gaze flicked downward for a second. I was genuinely worried my underwear might rip. I’d paid good money for them.
“Siblings should be honest with each other.”
“I am never showing you what’s below.”
“Didn’t shave? Don’t worry, I don’t care what it looks like down there.”
“You idiot. If you keep saying weird shit, I’m kicking you out. I already said I wasn’t showing you in the first place.”
How could someone a whole head shorter than me sound so threatening? Had she secretly hidden a gun somewhere?
Of course, I had no intention of forcing her to strip.
“You used to take off the panties you wore and give them to me. Why are you being so cold now?”
“Because it looked like you were going to fucking rape me. Take them and fuck off.”
“Then I’ll give you mine too.”
“I don’t need them. They’re too dirty even to use as rags.”
“Come on. You could just use them the same way I do.”
“Use them… you don’t mean……”
“I jerked off a few times thinking about you. Thank you so much.”
“You fucking bastard. Why are you explaining that in detail?”
“You’re the one who gave them to me. I just used them the way the giver intended. What’s the problem?”
“Then just use them quietly and leave me alone! Why the hell are you explaining it to me? I want to kill you.”
“I want a refill. With the ones you’re wearing right now.”
“What?”
“Why not? You can give your beloved little brother one more present. As you can see, I’m holding back so much right now. I’m trying not to jump on you, okay? Do you know how much self-control that takes?”
“……Then just cut it off.”
“But I need to see yours first.”
“Then show me and cut it off.”
“I’m not asking for a strip show. Just turn around and take off the ones you’re wearing.”
“Then pay me.”
“Can I pay in installments? How much?”
“You idiot. You’re actually trying to buy them.”
“You’re the one selling them, aren’t you? Then I’ll get a part-time job if I have to.”
“Haa, you crazy fuck. I wonder if Mom even ate seaweed soup after giving birth to you.”
“She gave birth to a sister who’s way more delicious than seaweed soup. That’s good enough. It’ll be fine, probably.”
“You idiot! I said no! Are your ears blocked? I’m never spreading my legs for you!”
“Who asked you to spread your legs? I just asked for your panties.”
“Anyway! And you. Why do you keep talking so much? Hurry up and take yours off too, you bastard. You get to watch me strip and now you’re—”
“That’s because… you’re the one who asked to see everything from soft to hard in the first place.”
“But… fuck.”
“For that to happen, obviously this thing has to go down first, right?”
“So? What do you want me to do? Hit it with a hammer?”
“I thought talking to you might calm it down a bit… but no luck.”
“……You can tell just by looking.”
“So what now? Still want to see it? Or should we wait a little?”
“Show me. It’d be unfair if I’m the only one who shows everything.”
“Is that really unfair? Your little brother wants it so badly. The least you could do is show him your tits.”
“It is unfair, you bastard. Just hurry up and take it off.”
“Haa.”
I sucked in a breath. Now that it was time to actually do it, I felt embarrassed too. Yunseo was staring intently between my legs. I slipped my hands into the waistband and slowly pulled my underwear down.
“Eek?!”
She let out a high-pitched squeak.
“……What? You told me to take them off.”
“W-why… why is it like that?”
“I told you. It got like this because you’re too fucking hot.”
“No, I mean the size. The size. Did you do something weird to it? Like pump air into it or something?”
What a cute imagination.
“You think it’s a balloon?”
“But why is it so big?”
“Our parents just made it this way. Guess the men in our family are all hung.”
“D-do I need both hands? Even then it feels like there’d be some left over……”
“Why? You gonna hold it for me?”
“You idiot, why would I—why, why, why, why would I touch your dick? That filthy thing.”
“You’re talking like you want to touch it. If you don’t, just say so.”
“Of course I don’t. It’s disgusting.”
“Just so you know, I wouldn’t mind at all touching yours.”
“You crazy fuck. What the hell are you saying to your own sister?”
Her words were harsh, but her eyes stayed glued to me the whole time.
“……Hey.”
“What?”
I was probably blushing as hard as she was. This was honestly really embarrassing.
“You know… when you do it while thinking about me… you move it up and down like this, right?”
“Wow, sis. You’re asking your little brother how he masturbates? You realize that, right?”
“……If you don’t want to answer, then don’t.”
“If you give me your panties, I’ll teach you everything. Even the stuff I don’t know, I’ll look it up.”
“You crazy bastard.”
“Heh. At this point, that doesn’t even feel like an insult anymore. I’m already crazy about you, sis.”
“……If I give them to you, how far will you help me? You mean with the novel, right? The novel.”
Who said anything about that?
“Anything you want.”
“Then can I tell you to go die?”
“Then I’ll fuck you senseless once before I die. Since I’m dying anyway, I might as well leave you with a kid who’s also my nephew.”
“You insane bastard. You fucking crazy retarded piece of shit.”
Her angry, ragged breathing kept brushing against my cock down below.
‘I’m seriously going to lose my mind.’
Sis. Please, I’m begging you. Stop doing that. If I really go crazy, I don’t know what I’ll do to you…… At the very least, please stop breathing on my dick.