The logic was flawed, the process was a mess, but the conclusion was absolutely correct.
"I don't care what kind of relationship you have. For the sake of everyone's health, this can't continue!" Kei Shirogane clenched her fists and pursed her lips, staring seriously at Rin Ito, who sat before her.
Regardless of how they got here, her goal remained the same: stop Moeha and Chika-senpai from living such a depraved life. Chika and Moeha had helped her so much; now it was her turn to save them.
The situation was actually better than she had initially feared. Before, she thought they were keeping Mr. Rin as a literal slave and that they would just find another man if she took him.
But now it was clear they weren't "buying" him. They were just... friends with benefits?
If they "gave" Mr. Rin to her, they wouldn't go looking for other men. After experiencing a man like Rin, they likely wouldn't have any interest in anyone else.
So... if she managed Mr. Rin, she managed them!
Facing Kei's determined gaze, Rin put on a troubled expression.
"This... might be a bit difficult," Rin paused. "I understand your concerns. Excessive indulgence is bad for the body. But... they're so cute, right? It's hard for me to say no when they want it."
"No! Your body won't be able to take it either, Mr. Rin! For your own health, you have to stop!"
Just as Moeha had said, despite her cold exterior, Kei was a genuinely kind girl.
Though her main focus was Moeha and Chika, she was also grateful for Rin's help. If she was going to save them, she might as well save him too!
"You need proper management. If you can't control yourself..." Kei bit her lip and looked away bashfully. "If you can't control yourself, I've heard of something called a chastity cage."
"Cough, cough, cough..." Rin nearly choked on his own spit. "Where did you hear about that?"
"Don't worry about where I heard it! If you can't control your impulses, I'll do it for you."
While she mostly studied legitimate academic materials, she had also searched for "wealthy woman lifestyle" topics... a chastity lock was one of the milder things she'd come across.
"Absolutely not."
Rin wasn't a masochist; there was no way he'd agree to that.
However, a chastity play was something Kaede—with her cuckold fetish—would probably love. Especially since her current mission was to find more like-minded "enthusiasts."
"Hmm..." After a moment of thought, Rin spoke. "Kei, you've done your research. You know a man's energy is finite."
"Yes, that's right," Kei nodded.
She had read that for young men, a few times a day was already the limit.
But Rin... last night, he had finished five times just before she blacked out. Not to mention he seemed to use his loads as facial masks for the others constantly!
His body was surely being pushed to the brink.
"I won't wear a lock, but I can let you supervise me. For example, if they want to do it, I'll have them call you. I only do it if you give me permission."
"That... fine."
After a moment of hesitation, Kei agreed. Having her supervise was better than them doing it behind her back.
Since they had "given" him to her, it was only natural they report to her. Plus, they might be too embarrassed to ask, which would naturally decrease the frequency.
But after she agreed, Rin continued.
"But Kei, you also know that if a man is 'full' and doesn't vent, it causes health problems too. You felt it last night—my body recovers much faster than a normal person's. So... for the 'excess' portions, will you help me vent them?"
"...You just want to fuck me, don't you?" Kei furrowed her brows, looking at Rin like he was a pervert. She wasn't an idiot like Chika; she knew exactly where he was going with this.
But after a brief moment of pursing her lips and frowning, she agreed to that too.
Her research had mentioned that long-term abstinence could lead to more than just "nocturnal emissions"—it could even cause varicocele, which was bad for the body.
Besides, Mr. Rin's body really was different. The sheer volume of a single load was enough to coat her entire face; he wasn't normal.
And he did it repeatedly. After so many rounds last night, a normal man wouldn't even be able to get hard, or if he did, he'd be shooting blanks.
Most men only have so much capacity.
But Mr. Rin... even after five rounds, his cum was just as thick and plentiful as the first. He was gifted. If he didn't vent, it really would be bad for him.
"Alright, it's a deal then." Rin clapped his hands and stood up. "I'll be in your care from now on, Kei."
"N-no problem. Leave your desire management to me, Mr. Rin."
"Calling me 'Mr. Rin' all the time is a bit formal, don't you think? How about a different name?"
"Eh...? Like what? Calling you by your first name feels... a bit rude." Rin was much older than them. Moeha and Chika could practically call him 'Uncle.' When Rin started college, they were still in elementary school.
Even the Nakano quintuplets' father was only a few years older than Rin.
But Rin only looked slightly more mature than their classmates. He could blend into a school without anyone noticing. 'Uncle' felt too old.
"Well... Moeha said you have a brother. Calling me 'Brother' might be confusing. How about... calling me 'Big Brother' like Moeha does?"
"Then... B-Big Brother." Even though she tried to keep her cool, distant school persona, her face flushed bright red the moment she said it.
Rin reached out and ruffled her silver hair.
"Since you've called me Big Brother, I have to give you a gift. Come with me."
Rin took her hand. Kei struggled for a second, but when she realized he wouldn't let go, she allowed him to lead her downstairs and out into the yard.
"I told you before that I know some beautiful light novel authors and artists your age. I wasn't lying. I rented the villa next door to use as a studio."
"...?"
Kei's blue eyes filled with confusion. She remembered him mentioning it when she was looking for a way to make money. But she couldn't draw or write; why was he telling her this?
"You said your home is tiny and you have to share a room with your brother with only a curtain between you. The studio mostly uses the living room, but there are plenty of empty bedrooms here. If you want your own room, you can move in here."
Rin paused and winked at her.
"I won't charge you rent. But in exchange, you'll help keep the studio clean."
Kei was proud. If she were willing to accept charity, she could have found a free place to stay long ago given her looks and the number of rich boys at Shuchi'in.
She was like Nanami; she wouldn't accept a handout. He had to give her a "job" to make it acceptable.
"Plus, living here means you can keep a closer eye on Moeha and Chika to make sure they don't 'sneak a snack.' So? Are you in?"
"I..." Kei looked conflicted. The temptation of a private room for a teenage girl was immense. But...
"Won't I be in the way?"
"Of course not. Some of the girls are novelists, some are artists, and one is a streamer. You can learn from them if you want."
"Mr. Rin... thank you so much."
Kei knew he was doing this just to help her. Hiring a regular cleaner wouldn't cost much, and letting her learn from geniuses was an incredible opportunity.
Mr. Rin really was a very kind man!
"Don't be so formal. Mr. Rin? What did you say you were going to call me?"
Kei's lips trembled as she whispered, "B-Big Brother..."
"That's better." Rin patted her head. "By the way... I feel like I'm already starting to fill up again."
"..."
Big Brother was indeed kind, but he really, really loved perverted things!