1.
In a quaint interior.
On the couch, covered with quilt, a fervor of passion gently flowed.
-Squelch! Swoosh!
"Haaah… Ahh… Mmph…"
"Gasp… Ngh…"
Alongside a pair of fingers moving in a constant rhythm like a metronome, the twins took turns singing in a seductive voice.
They no longer joked around with each other or talked to Siwoo.
Burying their heads quietly in the couch's backrest, they shook their butts, trying to indulge every drop of pleasure that was given to them.
Odile kept her mouth shut.
Meanwhile Odette bit into the quilt covering the couch.
The thin seals wriggled and twisted so delicately that it would be embarrassing to say that it served its purpose as a substitute for panties.
On the back of that thin paper lied pink membranes, eager to squeeze everything that entered them.
"Ohh… Mmh…"
Despite them being twins, their timing of experiencing pleasure wasn't exactly the same.
They squeezed his fingers at different moments, giving both of them different stimulations at different times.
"I'll speed it up a little."
Siwoo had been waiting for them to open their mouths as he slowly stimulated them with his fingers, but at this rate, it would take a long time to reach the result he was hoping for.
"G-Go on… Hyah!"
"D-Do it– Ahh…!"
Since he wasn't waiting for their response, he quickly increased his speed.
Disregarding the resistance coming from the membrane that squeezed his fingers tightly as he moved them around, he frantically thrusted at their holes at about triple the speed that he had previously used.
As he moved his fingers back and forth, he felt less pressure than before, indicating that their holes had loosened up quite a bit.
"Y-You're going…too fast!"
"H-Haah… Mmph!"
"Both of you seem to be enduring it well."
Whether it was Odile, who spoke with a high-pitched and quivering voice or Odette, who cutely covered her mouth, both of them looked adorable to him.
Odette, in particular, looked especially adorable as she jerked her smooth back several times.
Compared to Odile, who had sensitive breasts, Odette seemed to be more sensitive in her rear hole.
This was the secret that no one else knew about.
Every time Siwoo acquired embarrassing and lewd information about them, he felt a thrilling excitement about it.
To the point that he thought that it would be fine to stay and live in Gehenna.
-Slap! Slap! Slap!
"M-Mr. Assistant, wait a moment! C-Can you— give me a moment…to rest…?"
Amidst the vulgar sound of wet skin ramming against each other, Odette's pleading voice quietly echoed.
Suppressing her moans to the limit, she blushed with embarrassment.
"A-Aren't your hands tired… M-Mr. Assistant— Hngh!"
Odile also shot a glance over her shoulder, trying to tell him her agreement to her little sister's words.
But, would Siwoo stop after seeing such a reaction from them?
The answer was an obvious no.
It didn't take a genius to tell that they were slowly reaching their limits and that was why they made such a request in the first place.
"Okay, I'll increase the speed a little bit more."
Knowing this, instead of slowing down, Siwoo increased his speed.
He exerted all his strength to move his arms.
His movement was so quick to the point that he opened the eighth gate halfway.
"W-Wait, wait wait! D-Didn't you hear what I just said?!"
"Gasp… Heuk… Haah…"
Siwoo moved his fingers frantically, as if determined to tear their buttholes open, causing both of them to clench their buttocks tightly.
The pressure he received grew stronger and their intermittent spasms occurred more frequently. Too bad for them, his fingers had already found themselves in.
No matter how hard they tried to resist, they couldn't push his fingers out.
In the end, all they could do was to lower their waist and bear the torrent of pleasure that poured down like a waterfall.
"Haa… Ahh… Mr. Assistant— Mmph…"
Odile bit her lips as she couldn't hold back her moans when he tried to say something.
"Ahng! I like it… I love it when you do it from the back… Hauh… Fingers… Inside… It feels good…!"
Meanwhile Odette actively displayed her pleasure while appealing to Siwoo flirtatiously, as if a hidden switch in her had been flipped.
Feeling that their climax wasn't far off, the twins began to move their waists following Siwoo's movements.
"Mm… Ngh… Ang… Ahh… ?"
"It feels strange… Something weird is coming— ?"
Then their movements stiffened at once.
Their waists that had been moving around as if trying to escape from Siwoo's fingers were now gracefully arched like a bowstring, forming a smooth curve.
"Hiyaaah…! ?"
"Haaeung… ?"
An otherworldly symphony burst forth from both of them.
Siwoo's ears felt an immense amount of delight after hearing the unimaginably obscene voices from them.
"Oh, whoops…"
At the peak of their climax, as Siwoo inserted his fingers all the way in, the pressure he felt made it feel like his fingers were being cut off.
The twins kept trembling their buttocks and didn't let go of his fingers until the very end.
"Hoo… Hoo…"
"Phew…"
Watching the twins wriggling their pelvis while savoring the aftermath of the pleasure they felt, Siwoo pulled his fingers out with satisfaction.
2.
After the enjoyable symphony ended, the twins crouched down, trying to minimze the exposure of their naked body after noticing Siwoo's gaze.
Such action seemed inconsequential to him though, as they had willingly shown their butt to him.
"A-Anyway, are you going to put it in now, Mr. Assistant…?"
However, if they were to stop here, they wouldn't have started the whole thing.
Odile fanned her flushed face as she quietly called out to Siwoo.
The long awaited shimaidon had finally arrived.
Siwoo took off his clothes and threw them away.
"Ah…"
"Wow…"
"That's the biggest I've ever seen…"
The twins covered their mouths in surprise after seeing his erect dick, standing tall as soon as he undressed himself.
They seemed genuinely concerned about whether it could fit inside their bodies or not.
"Should we go as planned? Ms. Odile comes first?"
"W-Was that really the plan?"
Siwoo had anticipated Odile's reaction.
Pretending not to know, care and pretending that everything wasn't a big deal.
Unlike Odette, who stopped caring about anything once her switch was flipped, Odile still tried to maintain her dignity until the very end.
Despite her throwing a tantrum like a child to go first, she still acted as if she had forgotten everything.
While this act was natural for her, as someone who was pretty much a stranger to her and someone who was much older than her, Siwoo found the current situation incredibly awkward.
"H-Honestly, the order isn't really important, but if such an agreement had been made and you don't mind doing it with me first, Mr. Assistant, I don't have any reason to reject this proposal…"
It took her 10 seconds to say her very long winded and convoluted speech.
Then, she crossed her arms and quickly averted her gaze.
Her reaction seemed cartoonish, making Siwoo think that she might just be acting to hide her embarrassment.
"I've already done it before, so I'll yield this one for you, Sis!"
"Shut it, Odette."
Odette took the chance to stick out her tongue at Odile after hearing her words.
"Anyway, it seems that it's decided that I'll go first."
"Then, could you lie down for me?"
"Sure… Huh? Lie down?"
Odile habitually thrusted her ass backwards and turned her body around, but after hearing SIwoo's words, she raised her head in surprise.
Contrary to her expectations, Siwoo had his own plan.
Looking back, he had always been doing them from behind whenever he spent his time playing with the twins.
Of course, there was nothing wrong with watching the twins' backs trembling and twitching like young birds trying to flap their wings, but…
Both of them had taken off their clothes completely.
He wanted to do it while looking at Odile's face as he inserted his dick into her anus, seeing her breasts bobbing up and down as he thrusted.
There was no mirror here, it was impossible to see her expression if he were to do her from behind.
"O-Okay, i-is there anything else that I should do?"
Odile seemed to have no objections to his demands.
However, when Siwoo personally guided her body onto the couch, she showed a certain reaction.
Her eyes blinked in disbelief as she examined the position she had assumed.
"Are you sure this is the right position…?"
Doing it on a couch was different from doing it on a bed.
Since the anus was in a lower position than the pussy, if you were to do anal in the missionary position, it was inevitable for the girl to lift her lower body higher and spread her legs wide.
That was why the position Odile assumed was actually closer to the mating press rather than missionary.
Normally, doing it on the sofa would be quite challenging, especially if the girl's body was stiff, but Odile's body was remarkably flexible, so she had no particular problem in following Siwoo's instructions.
It was just, in her eyes, this position was too vulgar.
To her, only whores in Velvet Brothels would willingly assume this position.
First, she rested her neck under the couch's armrest.
Then, she spread her legs wide in a V-shape, drew her heels together and hugged her knees close to her chest.
Her ankles drew in close to her ears.
Thanks to this position, her dripping wet pussy, that was covered with the seal, proudly faced the sky while her butthole was completely exposed.
"…T-This is a little…"
"Are you embarrassed?"
"This feels somewhat humiliating…"
It felt like having him examine the most embarrassing parts of her body.
In a way, Odile wasn't far off.
The curves in her body became more pronounced with a level of detail that was notably different from what Siwoo could capture from a glance.
If he had a smartphone in his hand, he would undoubtedly take a picture of her and use it as a wallpaper.
"Don't worry about that. You look stunningly pretty."
He uttered the words that you'd only hear in dramas.
As he did that, he approached Odile slowly.
"Pretty, she looks like a toilet. See? Her legs is the toilet seat and—"
"Odette! Just keep quiet and watch…"
"But, I'm just telling the truth."
This time, she glared at Odette with a rather serious expression, but Odette just grinned in response.
"Ms. Odette is just teaching you, there's nothing strange about you at all, Ms. Odile."
"A-Are you sure?"
"Of course."
There was nothing strange to feel about. Besides, this was no time to hesitate.
If she kept feeling embarrassed and wanting to change positions, it would delay everything. That was why, Siwoo closed in and cut off her concerns.
After letting out a cough, Odile opened her mouth reluctantly.
"W-When will you put it in…?"
Siwoo held the glans of his cock and swiftly applied fragrance oil on it,
He slowly teased the glans against the entrance to her hole, which was proudly announcing its presence to him.
"Right now."
"D-Do it gently first, okay? G-Gently— Ah!"
Despite the change in position, the tightness of her hole remained the same.
Even though he was pushing it in very slowly and Odile relaxing her body to ease the penetration, his dick still wouldn't go in easily.
Her forehead wrinkled deeply, showing the signs of pain.
It seemed that she could only feel the pain at the moment.
Seeing her contorted expression up close, Siwoo felt a strange feeling, it was as if he was raping her.
That was how intense her expression was when he inserted his cock to her anus.
Normally, he thought of her as an innocent younger sister, but now, he looked different.
"Ah… ugg…!"
He suspected that the source of the primitive pleasure that he felt came from sin and the feeling of immorality.
Despite her grimaces of discomfort, Odile bravely held onto her legs and maintained her position for Siwoo. This gave him an overwhelming sense of dominance.
The scent of sweat emanated from her crouched body.
It was the pheromones that aroused Siwoo.
With each thrust he made, her eyes and mouth widened.
If Odile hadn't turned into a 'woman' at this moment, then what else would she be?
"Aaah!"
Hearing Odile's scream that sounded as if she had seen the end of the world, Siwoo finally managed to push his cock all the way into the deepest part of her hole.