It's a Big Problem Because My Little Sister (Black-Haired, I-cup, S-Rank Beauty) is Making My D*ck Losing It (Part 1)

T/N: in case you haven't noticed yet, whenever you see ( *** ) or ( * ), it almost always means a change of character point of view (from one character POV to another character POV).

***

"Unbelievable."

Stella muttered to herself "This can't be," twelve times, "Should I kill him?" seventeen times, "This is truly absurd," eight times, "Is he insane?" seven times, and "What is this?" eight times as she returned to her room.

There were no words to explain the emotions she was feeling right now or what had just happened.

She could only expel the frustration she felt at that moment with a sigh. For a long time, in Stella's mind, her big brother was a sinner.

She had been ecstatic at the prospect of having a big brother when she first heard the news. Her memories of those days when she eagerly anticipated her big brother's arrival, promising herself to do various activities together when he arrived, were now nothing more than a dark history.

The actual big brother who was adopted came to their house…

His appearance was quite different from Kim Sang-hyuk's current image, but she distinctly remembered feeling disgusted by him at that time.

However, this did not mean that she forgave Kim Sang-hyuk after becoming the "ideal big brother" now.

To be clear, the change in her feelings had nothing to do with her big brother's change in appearance.

Regardless of which brother it was, Stella had never considered allowing him to stay in this house with just Serena and herself. She held absolute authority as the judge, and her big brother was the sinner.

Entering the room with this stance, and the next thing she knew, she was on the floor.

'???????????????'

Stella's mind was filled with question marks.

No, is this guy really insane!?

He had declared that he would see her panties every time he wanted!

Although she fought with all her might, she realized that physical strength alone wouldn't work. That alone infuriated her.

'Why is this guy so strong!?'

She couldn't move a muscle and was unable to do anything. She continued to resist, but in a ludicrous turn of events, she found herself being strangled or rolling on the floor in various ways.

As if it weren't enough to just get down on the floor and beg for forgiveness...!

But then…

Stella was gradually feeling a sense of relief.

"When I want to see, I'll confidently go check out your panties," her brother's words had an oddly soothing effect on her tangled emotions.

What had tormented Stella up until now was, in a way, a pile of 'male hatred'.

He had objectified herself as a target of sexual desire, secretly installed cameras in the bathroom or toilet, taken pictures of panties, and so on… Initially, her big brother's actions had been terrifying and monstrous. An inexplicable fear had expanded to a simple hatred of the existence of 'men'. She had always been taught that a woman's chastity was precious, and it had been true.

Her big brother, who looked at that 'chastity' with lecherous eyes, had seemed like a terrifying monster.

Kim Sang-hyuk had been locked up as an epitome of disgust worse than a murderer in the prison his sister had created in her mind. This sense of loathing was endless.

During sleep, there's a possibility she might be assaulted. There was a possibility of her activities in the bathroom being secretly recorded. She didn't know what he might do with her underwear. He might tamper with her food.

Whenever she looked at a 'man', she had viewed them with such eyes, and her big brother was the perfect embodiment of that. After branding her big brother as a depraved sex offender, she had already cast all men, including Kim Sang-hyuk, out of her life. In the end, she had come to despise and hate all men, including Kim Sang-hyuk.

But today, she had rolled around with Kim Sang-hyuk like a wild animal. This wasn't the time to debate gender roles.

If she didn't release this chokehold, she would die! It hurt when he hit her belly!

In the midst of being tossed around by that primitive strength, she had become entirely nonchalant about revealing her underwear, regardless of whether it was a man or a woman. It was rather astonishing.

After all, this idiot would just say, "Hey, show me your panties," if he wanted to see them. Stella would respond consistently. "What are you saying? You're an asshole."

…She wouldn't use the word 'asshole' because that would trigger the chokehold.

Stella knew that Kim Sang-hyuk had genuinely opened up his innermost feelings, and it wasn't an act.

'This asshole won't be taking lewd pictures anymore.'

After gaining this newfound trust…

Stella realized that about half of her created fears had been processed internally. That bastard was at least not the type to use drugs or install hidden cameras to threaten her and Serena.

He was no more than a complete idiot.

You might not call this 'trust', but her interpretation of her big brother had certainly changed. Surprisingly, the weight on her mind had mostly disappeared.

Apart from her big brother, who had entered her life like a bigger asshole than she could have ever imagined.

"It's the first time I've writhed around like this."

Stella updated her brother's profile, previously labeled as 'Asshole', to simply 'Kim Sang-hyuk'.

***

For dinner, Serena had prepared pasta herself.

"Enjoy your meal, big brother."

"I will."

It was delicious. The level of pasta's cooking and the seasoning were just to my taste. Serena was quite a good cook. Excellent. The familiar smell of garlic with a hint of heat wafted from the pan where it had been sautéed1

.

"I also made Gambas2. Here, I've prepared some soft bread to go with it. It's good to eat together."

"Uh-huh…"

I could only nod repeatedly since the food was already full in my mouth.

"Big brother, ah~."

"Ah~."

Chewing and savoring… I gulped it down as Serena fed it to me.

Stella stared at it sideways, disgusted.

"What's up with your way of speaking?"

"Stella, too, ah~."

"When did you become so friendly with him?"

Despite her slightly displeased tone, Stella accepted the offering Serena extended.

Both of them, like hamsters, put food in their cheeks and chewed while gazing at Serena.

"Well, this morning?"

Cough! Cough!

I almost spat out my food.

"Big brother, you should also eat slowly."

The younger sister with black hair handed me a glass of water while smiling cheerfully.

…In a way, she seemed scarier than Stella.

Perhaps because I'm sharing a more significant secret with her, beyond stealing panties or taking pictures.

"Something seems suspicious."

A cold sweat trickled down my spine.

"Did Stella open her heart to big brother today too?"

"Open up? To whom?"

"Well, we ended up having dinner together."

"Well…"

Stella shot me a sharp glare.

"It's because I finally came out of my room. That's the only difference."

Me? Yeah. I guess Kim Sang-hyuk took on the role of a hikikomori3. Since Stella is always confident, she probably had meals with Serena.

From Stella's perspective, I, Kim Sanghyuk, would be an uninvited guest who intruded on the normal family mealtime.

"Now there's no reason to stay holed up. If you want to see Stella's panties, you can just ask."

"Who would show them?!"

"I already saw them today."

Shudder!

Stella crossed her thigh and glared at me as if she was annoyed.

"Don't fight, neither of you. Isn't it nice to have a meal together like this?"

"Okay, okay."

"Besides, if big brother wants to see, his little sister can show her panties~."

"That's not right."

"What are you saying? Are you crazy, Serena?"

Serena's and Stella's are breathing in sync. Serena clapped her hands in delight.

"Wow! We're breathing in sync!"

"…"

"…"

Their timing for opening their mouths was the same. It's normal to react like Stella when her big brother asks to see her panties… If you think you could potentially show them, it's actually scarier to be asked to show them. Because it feels like you might actually show them.

"Oh, big brother, you have a lot of laundry. Are you going to wash it all?"

"No, I was going to throw it away. Even with hydrogen peroxide and baking soda, the stains wouldn't come out."

What could have caused them to be so heavily stained that they couldn't get the discoloration out? It was a real mystery.

"What about your school uniform? It's a waste to throw that away."

"The size doesn't fit anymore. I grew a bit taller last night."

"Hmm… I can try to alter it for you."

"It would be faster to buy a new one. How much is a school uniform?"

"About 900 coins?"

…So, I'd have to defeat a goblin horde eighteen times to afford it? I checked the number of coins on my Student ID.

[Kim Sang-hyuk]

[Current Coins: 54]

'Not going to happen.'

If I accumulate too many violations of the dress code while earning money, won't I end up being summoned to the Student Council again? I haven't been exempt from my sins; I'm just on probation. In the meantime, if I cause an incident, I'll face more severe punishment. Even a child could understand the implications of that.

"Please, Serena."

"Leave it to me, big brother! I'll handle it smoothly."

"The early bird gets the worm."

Thud.

Stella puts her bowl in the sink and runs upstairs. We watch Stella's back as she goes.

"So, what do you think? Any chance of reconciliation?"

"She gets lonely easily, so if big brother keeps shaking her, she'll come around soon."

"I can hear you!!"

She'll come around. I hope so. I wish the house could be peaceful…

There's nothing better than having pretty younger sisters who keep me company and get along with me well.

A little while later.

"Big brother, can we sleep together?"

'This one seems to be getting along with me too well.'

Bedtime.

I feel dizzy as I watch Serena, who is sitting curled up on her stomach in the doorway.

[Serena]

[Conquer Difficulty – (A-)]

[Onahole Aptitude – S+ Rank]

[Prelude Quest – (A-)]

[Prelude Quest 2 – (A-)]

[First time was with Big Brother♡]

[Underwear – Black panties with little coverage. Serena's sports underwear (no bra)]

[Onahole Features (★) – This younger sister has an amazing figure! She boasts a perfect body balance with exceptional volume, and an insatiable desire that can't be resisted once experienced. She is a devilish younger sister onahole.]

[An ideal younger sister who loves and follows her big brother very much. She is pretty, shy, and a model student. At first, she doesn't easily give in to physical advances, making it difficult to start, but once the fire ignites, her passionate side that can't stop yearning for you shines through. Whether it's a girlfriend, wife, sex friend, younger sister, older sister, or a forbidden relationship, she can play any role as a hexagonal onahole4.]

…I didn't want to know that my younger sister is a hexagonal onahole.

Appearing in a semi-transparent shirt with black lace underwear, I don't know where to look anymore. I hold the pillow tightly and Serena looks at me with wet eyes.

Is it just me, or does this whole production feel very contrived? This is a clear temptation.

Or is it? Is it just that I'm too dirty minded?

"…Do close siblings engage in such activities together?"

Let's make a sound judgment, Kim Sang-hyuk. But I'm an only child, so I don't know for sure. Seriously. I recall the experiences of mingling with cousins of the opposite sex during the holidays.

Not much of a reference. One thing is for sure, the atmosphere back then wasn't as sensual. My cousins seemed like creatures somewhere on the border between monkeys and humans to me, so there was no thought of getting entangled with them.

…Just the thought of sleeping with Serena.

"Big brother… I'm scared to sleep alone."

I gulped. 

Her skin, which seems to retain moisture just after a shower, looks incredibly smooth. Serena's violet eyes, standing in the dimly lit corridor where most of the lights are turned off, exude a mysterious charm and softly glimmer.

"You're all grown up, but you're scared to sleep alone?"

"Yeah."

"Then… Come in."

With permission to enter the room, Serena immediately changes to her playful smile and rushes into my arms.

Hug!

"Hehe!"

"You…!"

"Scared to sleep alone, do you think I'm a little kid, big brother?"

It's not that I think you're a little kid; the problem is that you're a fully grown adult! Gah, no bra? Serena squeezes and even playfully rubs her breasts, leaving me with no resistance, and I become aroused. Serena smiles smugly as if confirming her attractiveness.

I try to shake her off, she won't let go. Serena seduces me by rubbing her breasts.

"Ugh~ Big brother, why do you keep hesitating?"

"I, if Stella finds out…."

"Hehe, it'll be a big problem. If Stella finds out that you and I have already had sex."

"…W-what sex?"

No, not sex!

"You said it was a mistake."

"Big brother, are you trying to avoid responsibility?"

"It's not that. It's just that mistakes happen! It's for the sake of your future husband."

Serena stopped abruptly and looked up at me.

"…I thought you already knew?"

"What…."

"The feeling when you filled me up to the root… The reaction I showed when I was completely yours, the sense of unity we felt when we became one."

"…"

"I remember when… I felt like I had no choice but to be my big brother's woman… You made me swear to you when you were inside your little sister's baby room5."

With each word Serena spoke, I became dizzy.

Oh, is that so?

Is there really no turning back?

The feeling of my intelligence declining due to the rubbing breasts on my chest.

"Am I really still a virgin, big brother?"

"…Ugh, ugh."

"Didn't you fuck me a while ago...?"

"No."

Just like that. I have to forcefully think that way, or else it's dangerous. Our relationship.

"But…"

I firmly grabbed Serena's slender shoulders.

"Oh, big brother?"

"If you don't want it to be a mistake, I'll take full responsibility."

If Serena's heart felt that way, I…

"Would it be alright if you became my lover, big brother?"

"..."

Serena had a dazed expression, as if she were somewhat intoxicated.

"Then let's go tell Stella. About what happened between us."

Whether my sincerity got through to her or not, Serena suddenly snapped to attention.

"Oh, no!! Big brother… I was just fooling around because I found it funny."

"Joking? Do you have something else to joke about? Are you really trying to get in trouble?"

Whew…

I breathed a sigh of relief inwardly. It seemed like it was still okay for her to be my little sister.

"I'm sorry. I didn't mean to act like I had caught you in a weak moment…"

"An accident… Right?"

"Yeah. It was an accident, anyone could see that. Don't feel guilty, big brother."

Yeah…

Losing your virginity after falling over is just ridiculous. That's something we shouldn't even count as a first experience.

"…Was what you said earlier a joke too?"

"…What do you mean?"

"The part about filling you up… and…"

Serena just laughed, seemingly enjoying herself.

…I'm sure it was a joke.

My handsome cock didn't happen to have that wicked effect like 'Once a woman tasted it, she can't turn back', right?

Right, Goddess?

Serena's future husband, Serena is a proper virgin in both mind and body. Let it be so. I shiver at the thought of ruining Serena's life.

"So, are we going to sleep together now, big brother?"

"…Huh? Is that so?"

"Yes. Everything's all set. All that's left is sleeping with my reliable big brother!"

"...???"

Huh? Is this right?

Led by Serena, I entered the bed with her. She looks happy, so is there no problem…?

After turning off the lights, it's a dark room.

I feel Serena's skin and body temperature, and we entwine with each other. Serena doesn't seem at all bothered by my erect penis, but instead burrows into my arms.

"I'm glad you're my big brother."

"Well, how long has it been since we met…?"

"It's been a few years."

Oh, right. From Serena's perspective, it was like that.

"But, out of all the years I've known big brother, today's big brother is the best of them all."

"…."

I thought there wouldn't be a more embarrassing thing to say than Stella's 'Just die, big brother'.

"Big brother, I love you."

This time, it felt like my brain was melting.

After a while of being tangled together, I gently asked, touching Serena's bangs with my hand.

"…. You mean, you love me as your big brother?"

My face grew hot. What am I asking my little sister? 

If she loves me as a man, how should I respond? 

Should I touch her right away?

Serena fell asleep peacefully in my arms.

'….'

Sigh….

I decided she would have answered 'big brother'.

Serena is just happy because she has a big brother to pamper her.

If I had reacted seriously and tried to take action, she would have responded the same way when I grabbed her shoulders just now. So…

What I must do as a man is not to touch Serena even if she offers me as much space as the Pacific Ocean.

"…This is the most difficult thing I've done today."

My penis got erect, which was a big problem.

(End of Chapter 13)

Sautéed is a cooking technique where food, often small pieces of vegetables, meat, or seafood, is quickly cooked in a small amount of hot oil or butter in a shallow pan over high heat.

Gambas typically refer to "gambas al ajillo," a popular Spanish dish consisting of shrimp or prawns cooked with garlic and chili peppers in olive oil.

Hikikomori, also known as severe social withdrawal, is total withdrawal from society and seeking extreme degrees of social isolation and confinement.

Hexagon has six sides just like described 'she can play 6 roles'.

"Inside you little sister's vagina (baby room)"