Next Day
"...Noona. It's me."
"Door's open. Come in."
Before opening the door, I took a deep breath.
How much had I agonized over coming here?
I'd thought and thought, but all I did was waste time and stress myself out.
This was a problem with no right answer from the start.
Steeling myself, I opened the door.
Noona was sitting at her vanity, fixing her hair.
She must have been getting ready for bed, wearing only a thin slip.
Beneath it, I could see the outline of black lingerie.
She always dressed like this at home, but today, it felt especially provocative.
"Why so late? I was about to come find you, thinking you were skipping on the first day."
"...Sorry."
I wanted to tell her to stop this.
I wanted to say we should go back to being normal siblings.
But the moment I saw her, all my practiced words vanished, and all that came out was an apology.
"Whatever. Are you about to jerk off now?"
"..."
"Not answering?"
Through the mirror, Noona's eyes locked onto mine.
I swallowed dryly and nodded.
"…Yeah. I'm about to."
"Good. You're gonna do it properly while thinking of me, right? Got it?"
As she spoke, she stood up.
Then, placing her hands on her hips, she slowly slid her panties down.
I flinched and turned away at her sudden action.
What the hell was she thinking, stripping in front of her little brother like this?
"Here. Today's material."
Something light landed on top of my head.
Material…? No, it couldn't be what I was thinking, right?
Carefully, I reached up and grabbed whatever had been placed on me.
The soft texture of fabric met my fingers.
Looking down, sure enough, it was the panties Noona had just been wearing.
Dark Red with semi-transparent material.
It was a lewd piece of fabric.
And she'd called this today's material.
Just like yesterday, she wanted me to cum on them.
Noona sat on the edge of her bed, crossing her legs as she stared at me with sharp, focused eyes.
Was she enjoying how flustered I was?
Stammering, I tried to force out some kind of protest.
"N-Noona. This is too…"
"Why? Don't like them?"
A small smirk tugged at her lips as she shifted, uncrossing her legs and crossing them the other way, never breaking eye contact.
The pale skin of her thighs peeked out from beneath her short slip, drawing my gaze.
And right now, she wasn't wearing any panties.
If I just leaned in a little… I might catch a glimpse of her most forbidden place.
The thought alone made my heart race and my body heat up.
But that was the Bermuda Triangle down there.
If I let my eyes drift toward that forbidden zone, I'd be pulled in… and there'd be no coming back.
To avoid that fate, I mustered every ounce of willpower to look away.
"...Fine. I just have to cum on this, right?"
"You catch on quick. And when you're done, you come straight to me for inspection. Got it?"
"Inspection..."
Did that mean she was going to check if I'd done it properly?
...What did Noona want to do?
Was it simply that she wanted to tease me, or did she have some other purpose...?
I had no idea what was going through Noona's mind.
But even if I resented it, I couldn't defy her.
If Noona told me to do something, I had no choice but to obey.
After leaving Noona's room, I returned to mine and locked the door.
Just like yesterday, this time had come again.
The time to masturbate with Noona's underwear.
I took off my pants and lay down on the bed.
"Ha..."
A sense of relief at being in my own space.
And at the same time, a wave of shame over what I was about to do.
But I had no other choice.
The best course of action was to finish quickly, without thinking too much.
I grabbed the panties Noona had given me with both hands and unfolded them.
The panties that was on my big sister just moments ago.
Nearly half of the material was so transparent, that her most intimate parts would be clearly visible.
Did she always wear panties like this?
Did she wear them to show off to someone?
Though there had been plenty of dating rumors about my sister, I'd never heard of her actually seeing anyone.
But just because I didn't know didn't mean she didn't already have a boyfriend.
A boyfriend who got to see her wearing panties like these.
I couldn't help it, the thought made my chest tighten uncomfortably.
Perhaps because she'd worn them right after shower, the scent of fabric softener was stronger than yesterday.
We used the same fabric softener for my clothes, but somehow, hers smelled different.
"Noona..."
The image of Noona taking off her panties came back in my mind.
If I hadn't looked away back then, maybe I could've seen everything properly.
Even when she was sitting on the bed, if I'd just shifted my gaze a little...
I began stroking myself, filling in the unseen parts with my imagination.
***
Knock, knock.
"Noona. I'm done."
"Come in."
Hearing her response, I entered her room.
Since when had stepping into Noona's room become such an difficult task?
Noona, who had been lying on the bed, sat up when she saw me.
Afraid I might catch a glimpse of something I shouldn't, I averted my eyes slightly.
"...I did it."
"Yeah? Hand it over."
Noona reached out to me.
…Did she mean the panties?
Right now, Noona's panties were soaked with my cum.
Honestly, even I didn't want to touch them.
Was it really okay to give something like this to Noona, who had such strong germaphobia?
"What're you doing? Hurry up."
As I hesitated, Noona urged me on.
Reluctantly, I placed the crumpled panties in her outstretched hand.
"Let's see. Just how much did Woojin shoot today?"
"N-Noona."
Noona spread the panties open without hesitation, right in front of me.
The sticky, white mess clinging to the red panties was exposed.
"That's a lot. And the smell is also strong. Did it feel good?"
I couldn't speak, bowing my head instead.
My face burned with shame, like it might explode.
"Hmm. Woojin came on the inside of the panties, huh? Do you know what that means?"
Noona asked with a playful smile.
The inside of the panties?
Did something like that even have a meaning?
"Ejaculating on the inside of panties. The meaning behind this act is, 'I want to impregnate the other person.'"
"Wha...!"
Of course, I had no idea about any of that.
I'd just done it without thinking.
"I see~ So, Woojin, you wanted to knock Noona up?"
"N-No, I didn't know about that..."
"These things are usually subconscious truths. It's like a psychological test."
That's a lie.
Who in the world would create and prove a psychological test like that?
Noona laughed cheerfully before asking me:
"Well, Woojin? Do you really want to get Noona pregnant?"
"I-I don't, I just..."
"Hehe."
Noona gently stroked her lower abdomen.
As if there were already a baby inside.
I didn't know what that gesture meant.
But for some reason, I couldn't tear my eyes away from her hand.
"Right. If I wore these panties to sleep like this, wouldn't I get pregnant? If it's Woojin's healthy sperm, it'd climb up through my pussy and reach my womb, wouldn't it?"
"...What are you saying, Noona? Th-That's impossible, right? There's no way..."
My lips felt parched.
I didn't understand why Noona was saying these things.
Why would she even consider putting on cum-stained panties in the first place?
No, she was definitely just teasing me.
Trying to mess with me.
There was no way my germaphobe Noona would wear panties dirtied with cum.
So I shouldn't panic.
The more flustered I got, the more she'd enjoy it, and the worse her teasing would become.
"Or what if I wore these and ran to the police station, crying?"
"Noona!"
I told myself not to panic.
But Noona's words were impossible to ignore.
"They could analyze the DNA from the semen on these panties and immediately trace it back to you. Then you'd become the most notorious sex criminal in the country, the boy who raped his own sister."
"If-if you did that, Noona would also..."
"Yeah, you're right. I wouldn't be able to show my face in public again. Neither would Mom or Mia. Ahh, what a tragedy. To think our family would be ruined all because of some outsider's child."
I could only stand there trembling as I listened to Noona's words.
Because of me, our family would suffer.
What Noona was describing was the most horrifying scenario I could imagine.
Just picturing it made it hard to breathe.
"So, come early tomorrow. If you listen to Noona, I won't tell anyone. Understood, Woojin?"
"...."
Her slender fingers brushed against my earlobe.
It felt like a lion licking the back of my neck.