Despite being his fourth release, the volume showed no sign of diminishing.
The thick, white fluid gushed out with a plop, plop, streaming down the glans and coating Matsuri's hand.
"Whoa!"
Startled, Matsuri quickly withdrew her arm.
The overstimulated penis continued to spasm uncontrollably, pathetically dribbling semen.
"...I did it... I made him come..." she murmured, watching with fascination as the penis began to shrink.
Once ejaculation was complete, she stared intently at the sticky substance covering her hand.
Matsuri prodded the semen with her finger, testing its texture with a mixture of curiosity and amusement. Eventually, she held her hand out to Miki.
"Look, Miki~! See how much there is?"
"Wow, amazing as always, Matsuri-chan!"
"Hehe, it's easy, really."
Miki clapped her tiny hands.
Encouraged by the reaction, Matsuri snorted triumphantly and shot me a scornful glance.
"Ugh, gross! Having my younger sister mess with me and make me cum is so embarrassing. And look at how much you're leaking! Aren't you ashamed? Pervert!"
There was nothing I could say in response. I slumped back against the chair, wiping the semen away with a tissue.
Once I'd come and my brain snapped out of its weird trance, a wave of vague emptiness and humiliation washed over me.
For some reason, I felt strangely aroused. Worse than when it happened with Miki...
I'm not some creepy older brother obsessed with his sister, am I? This has to be Miki's fault—those lewd whispers of hers. It's definitely, absolutely her fault.
"Heh, you were whining about it not feeling good, but you're totally coming! So pathetic. Hilarious."
Grrr... What humiliation.
But with my penis still exposed after coming, there was no way I could win any argument.
This was a crushing blow to my pride as an older brother, my dignity... I never realized how much it would sting to be made to climax by my younger sister.
"This is dirty. I'm going to wash it. It smells, too. I need to disinfect it properly."
Matsuri looked down at me, basking in her superiority for a moment before abruptly leaving the room.
After watching her go, Miki turned to me with a dreamy expression.
"Haaan, Matsuri-chan is just adorable. She's the best, don't you think?"
"Uh... I guess..."
"Oh, come on! When she glared at you earlier, you totally reacted differently! You're a tsundere, aren't you, big brother?"
"No, that was because Miki-chan provoked her..."
"Aw, are you making excuses? Hehe, I think we're going to get along just fine. Just as I suspected!"
Now she thinks we're weirdly close.
Just as I thought, she thinks I'm a massive siscon.
"...So, um..."
Miki squirmed a little, a sinister smile spreading across her face.
"Don't you want to see Matsuri-chan's... more ecchi side?"
What is she saying now?
No, no, that's just Matsuri. That was just a momentary lapse in judgment.
Besides, talking about my younger sister like that? That's definitely out of bounds.
"Huh? N-no, that's a little..."
As I hesitated, Miki moved right up to me.
Then, before I could react, she took my hand and abruptly guided it under the hem of her dress.
"Seeing you just now... it made me get like this."
The hand Miki had pulled toward her touched damp fabric.
After moving my hand up and down several times over the fabric, she gripped my fingers and pushed them further into her underwear.
Her fingers parted the hair, reaching a thoroughly damp area. Then, Miki raised the tips of her fingers, forcing them deeper.
Squelch.
The tips of her fingers sank lightly into the soft flesh.
The slippery sensation of her fingers made my face flush instantly.
Could this feeling...? No way.
"Ah, it's getting hard again. It's really obvious, isn't it?"
My penis had regained its hardness.
Obvious? This is my first time touching a woman's intimate area. It's a perfectly natural reaction.
Miki gently cradled my erect penis in her hand.
At the same time, she leaned close to my ear and whispered:
"...If you get even more aroused, your 'this' might be begging to be 'here'."
...What did she just say?
Miki pulled my frozen hand out of her panties.
The trial period lasted only a moment, but its promotional effect was outstanding.
I immediately pounced, eager for details.
"S-so, 'aroused' means...?"
"I don't usually get this worked up over much... even I was surprised. There's just something about the taboo thrill of being a brother and younger sister, right? And when that younger sister is Matsuri-chan, it's even more intense."
Lost in thought, Miki gazed off into the distance, her expression dreamy, as if reliving the earlier scene.
"I just love cute things! That's why I want to see Matsuri-chan's cute and ecchi sides! Well, I still like penises too, but lately I've been a bit bored with them, you know, it's getting a little stale."
Even with such an honest and direct appeal...
This is definitely a bitch. A total bitch. And a two-timer at that.
"I was planning to show Matsuri-chan some accidentally discovered porn on my computer today, hoping to wear her down, but she seems like the normal type. I might end up getting rejected."
"Sorry, I'm not really sure what you're saying."
"I was prepared to force it if necessary, but I was wrong. It's crucial for Matsuri-chan to do things of her own free will. That's what really gets me excited."
I still think she's got a lot of misconceptions...
From the outside, you'd never guess it, but could this girl actually be quite dangerous?
"That's where you come in, big brother. Let's spoil Matsuri-chan together, okay?"
"Huh? Why does that involve me?"
"Come on, Matsuri-chan definitely has a crush on you! I'm so jealous of you!"
"No, no, no, that's not it at all!"
"If that wasn't the case, she wouldn't have done what she did earlier, right?"
"That was just Matsuri's intense competitiveness flaring up."
"Miki-chan must have riled her up, stoking her competitive spirit."
"Besides, she's so used to people touching her penis or whatever that it doesn't bother her at all."
As I grumbled these excuses, Miki replied with an unconcerned expression.
"I know all that. Her stubbornness and willingness to compete fiercely is cute. But you're making one major mistake, big brother."
"Sigh..."
I wanted to retort that she was the one making the mistake, but Miki suddenly looked deep in thought, her expression contemplative. I obediently fell silent.
But she quickly seemed to have an idea. Miki slapped her hand excitedly and grinned.
"Alright then, let's make a bet."
"A... a contest?"
"If I win, you'll have to do as I say from now on... Oh, or just cooperate with me, I guess."
"You just rephrased it, but that still sounds ominous..."
"Still, if you win, Shio..."
"W-win?"
What is this? I don't know what kind of contest this is, but I have a vague, erotic premonition.
If I'm going to win, I'd like something a little hands-on.
Miki gave me a meaningful smile, as if she'd read my mind. "Where my finger went earlier... that..."
She pointed at my erect penis.
"I'll let you put that inside me."
"W-what?! No way!"
That proposal far exceeded my wildest expectations.
I-is this for real? Is this actually happening?
Is it really okay to just... slip that in so easily?
I thought there would be all sorts of annoying initiation rites, but to think I could just skip that impossibly long journey and score a direct goal?
And with such a beautiful girl, no less... the ultimate prize...
I have to say, "Hooray for bitches!"
"S-so, what's the challenge?"
"Whether you can last three minutes during a handjob from me."
"T-three minutes...?"
The sudden mention of a handjob caught me off guard, but three minutes...?
What's three minutes, anyway?
Matsuri's earlier performance—though I didn't time it—felt like at least five minutes, maybe even ten?
My perception of time was warped by arousal, so I can't be sure, but three minutes? That might be manageable.
I wasn't sure about the first time, but today I've already released quite a lot—four times, to be exact.
Even if this doesn't work out, since we're going to be collaborating from now on, I'll still be able to stay connected with Miki-chan. So either way, this situation seems pretty sweet for me, doesn't it?
As my mind raced with indecision, Miki casually remarked:
"Ah, but if I put this super-fast-shooting penis inside me, it might start gushing inside me right away. This is overwhelmingly unfair to me, don't you think?"
Wait, is she suggesting... an actual cumshot?
And without a condom?
"So, what'll it be?"
"Yes, let's do it."
I answered immediately.
When I agreed, Miki flashed a fleeting, ominous smile that gave me a bad feeling. But my skyward-arching penis seemed to be urging me on.
In the end, I couldn't win against my lust.
Once the decision was made, Miki brought over some lotion and drizzled it directly onto the glans.
It was slightly cold at first, but Miki's warm hand soon enveloped it.
"Alright, let's begin. Just a little longer—let's wait until the six minutes turn into seven. Ten minutes in total."
Miki knelt before me as I sat in the chair, glancing at the digital clock on the desk while gently grasping my penis.
Seven minutes. Ten seconds to go. A strange tension filled the silent room.
For some reason, I recalled a gunslinger from a Western. Who's gonna win a quick-draw duel anyway?
The moment the clock hit seven, Miki's hand erupted into furious motion.