The Rope's True Purpose
The rope had originally been prepared to bind Lua herself. Just in case things grew too intense and she ended up hurting her brother. After discussing it with him, she had planned to restrain her own arms and then soothe his cock. After all, even if she tied her legs as well, Lua could still easily devour Sia.
“Ah…… ugh……!”
That very rope was now being used to torment Sia's fragile body. Both wrists were bound together and suspended from the ceiling. Each ankle was tied with a separate rope and anchored to opposite walls. Sia was forced to hold her arms high above her head, legs spread slightly wider than shoulder-width, knees pressed into the bed. Maintaining such a posture was incredibly taxing on Sia's weak stamina.
“L-Lua, this is…… too…… ngh…… hard……”
Sia had made a promise. If it ever became truly unbearable, she would address Lua as Your Highness the Grand Duke. The fact that she hadn't yet meant she could still endure.
“Haa…… haa…… Brother, your moans are so lewd……♥”
Squelch. Squelch. Squelch.
For quite some time now, Lua had been standing behind Sia, stroking her massive cock with both hands. Sia's nightgown was a sleeveless design with an open shoulder and a long skirt. Simply being bound by thick red ropes while still fully dressed created an obscenely erotic sight.
“Hngh……”
When Sia lowered her head in exhaustion, her hair cascaded down, exposing the elegant line of her spine and the nape of her neck. Her slender, unblemished white neck looked like a masterpiece carved by a master sculptor. And when she tilted her head just slightly, the glistening sweat in her armpits came into view. Lua felt deeply satisfied, convinced she had captured the perfect angle.
“Ahh♥ I-I'm gonna…… ngh…… cum……!”
Splurt— Splurt—
As ejaculation began, Lua's face melted with pleasure.
“Ugh…… hngh♡”
Thick, steaming-hot semen splattered across Sia's delicate spine in heavy ropes. Feeling the sticky fluid trickle down her back, Sia shuddered violently. The overflowing cum soaked into her pink hair, matting the strands together. The sight of her instantly ruined by white filth filled Lua with overwhelming conquest.
“Ah—♥ So good……♥”
“You came, right? So we're done now……? L-Let me go……”
“I don't think so? Seeing you struggle like this got me hard again♥”
To be precise, it hadn't gone soft at all. Lua rested her heavy cock against Sia's spine. The sheer rigidity and weight made Sia's body crawl with goosebumps.
“Huu…… Where should I use as a toy this time?”
“S-Stop it already……”
“Don't say things you don't mean, you bitch. Ah, this looks perfect♥”
Lua reached down to lift Sia's long skirt. As the fabric rose, her pale, soft thighs were laid completely bare.
“Hiiyah!”
“Why are you so surprised? Hehe♥”
Lua assumed Sia was startled by having her most private areas forcibly exposed. Come to think of it, though they had done all sorts of obscene things, this was the first time she had actually stripped her.
“Whoa—♥”
Her ass, spread wide and plump like flower buds. The way the flesh beneath her panties bulged out against the fabric was breathtaking.
“Hic!”
“……Brother?”
The skirt was already rolled up, so there should have been nothing left to surprise her. Yet the scream felt strangely off. Lua quickly noticed and slid her hand up Sia's thigh with a wicked touch.
“Kyaa?!”
“Ah, I see. This is the first time you've been touched like this, isn't it?”
“I-It's ticklish……! Hngh♡”
Like spider legs gliding across skin, Lua gently stroked Sia's thighs. Sia had called it ticklish because she had no other words, but the sensation was something else entirely. It felt like lightning racing across her waist. A bizarre feeling that made goosebumps rise and her spine straighten involuntarily.
“L-Lua, this feels weird♡”
“Hehe. I'm sorry. I've been enjoying myself all by myself this whole time.”
Sia had calmed Lua's cock countless times, yet Lua had never once done anything for Sia in return.
“I-I……!♡”
When Lua squeezed her ass cheeks hard, Sia's pelvis twitched so violently she couldn't finish her sentence. She had only meant to say that since Lua was the one overwhelmed by lust, there was no need to do this to her. But Lua had become completely addicted to forcing things on Sia against her will.
“This is the pleasure a female body can feel, you know?”
“I'm f-fine, so stooop!♡”
Lua slid her hand over Sia's clothes and placed her fingers on a nipple. She pressed the stiff, erect bud, circled it, then gently scraped it with her fingernail.
“Hngh♡ Haaang♡ S-Stop……!”
Just like when Lua had first used her cock, Sia was now experiencing a pleasure she had never felt before. Faced with such an unfamiliar sensation, what she felt wasn't joy, but fear of the unknown. Teeth clenched, drool spilling from lips that refused to close, Sia endured the overwhelming pleasure.
“And here…… like this……♥”
Lua pressed a finger against something protruding from Sia's pussy. In that instant, Sia felt as if time had stopped.
“Haaah♡ Aaaahng!♡”
Sudden ecstasy surged to its peak. The world turned white, as if caught in an inexplicable explosion. At the same time—pshhht—something gushed out of her. It felt similar to urinating, so she tried to hold it back, but it was impossible. The pleasure that came with the release was the same, yet entirely different from excretion. It felt like her soul was being sucked out. Almost exactly like the ejaculation she had felt as a man. Her panties grew soaking wet.
“Oh my, Brother…… did you just cum?”
“Haa…… haa…… C-Cum……?”
“Yes. It looked like a magnificent female orgasm, didn't it?”
Squelch.
“Hiiik!”
Lua's fingers continued to explore Sia's pussy. The fabric clinging to her plump, soaked labia was drenched with her juices.
“Nngh……♡”
“Look at you, dripping like this.”
Lua grabbed the panties and yanked hard. Sia immediately realized what she was trying to do.
“Y-Your Highness the Grand Duke!”
“Ugh……!”
At her brother's desperate cry, Lua's sanity returned and her hand stopped.
“T-This is…… a line that must not be crossed…… I think……!”
No matter that they were siblings—or rather, precisely because they were siblings—exposing her genitals was far too shameful.
“……That's unfair.”
“Eh……?”
The voice was low and filled with disappointment. Sia shuddered at its coldness.
“I've shown you my cock over and over and over again.”
“T-That couldn't be helped……! I never asked to see it, you just did it on your own……!”
Sia realized she had misspoken. The reason Lua's cock had grown erect on its own was entirely because of the curse Sia herself had created. It wasn't that her little sister had shown it on purpose.
“Either way, you saw it.”
Fortunately or not, Lua didn't seem upset about that part. The hand gripping Sia's panties tightened again.
“Hngh! L-Lua! We agreed you'd stop if I called you Grand Duke!”
“This one doesn't count. Your attitude is too cheeky, Brother. Since you've seen mine, you have to show me yours too!”
It was a childish whine that seemed impossible coming from a Grand Duke. This was the voice of a Grand Elf whose reason had been completely stolen by her cock.
Riiip!
“Kyaa!”
In the end, Sia's panties were torn away by Lua's hand and fluttered to the floor like fallen leaves.
“Haa…… haaa……♥ This is…… Brother's pussy……♥”
The word Brother carried the meaning of male, while pussy carried the meaning of female. The contradictory combination filled Lua with ecstasy.
“Ugh…… ugh…… You're so mean……”
In contrast, Sia fell into despair. She didn't want anyone to see the sight of her crotch where what should have been there was now gone. That emptiness. That misery. That sense of loss. That frustration. Overwhelmed by shame so intense it felt like her brain would burn, Sia trembled violently as tears streamed down her face.
That wounded appearance only made Lua's cock throb with even greater fury.
Squelch, smack, smack, squelch, squelch.
“Aah, Brother, you're so beautiful…… ngh……!♥”
Splurt— Spluuurt—
“Hngh……♡”
Using the agony her brother felt as fuel, Lua came once again. Sia squeezed her eyes shut against the cum splattering across her face and let out a moan. No matter how little pride or self-respect Sia had left, this was still far too humiliating for someone born of Grand Elf bloodline.
Right now, Sia wasn't being treated as a person, nor even as a beast. She was something beyond a mere tool for relieving lust—just a male's masturbation aid, nothing more than an ornamental piece.
That's right. That's all the value I have. That's enough. ……But, ngh…… my lower belly is reacting again……♡
Even though her heart should have been in pain, for some reason her lower abdomen was throbbing once more.
Lua moved to observe Sia's genitals. Between her straight, spread legs, a pure white mound with plump, tightly closed pussy lips. Just like Sia was crying, her pussy was dripping with arousal.
“As expected, Brother really is a perverted masochistic bitch, isn't she? You're getting off on this humiliating situation.”
“N-No. I'm not feeling anything.”
“With your pussy juice flowing like this, how can you say that?”
Lua possessed basic sexual knowledge. Since she wasn't a man, she hadn't known how to use her cock at first. But even then, she had understood why a penis was shaped that way. And of course, she understood even better why a vagina looked like this.
So this is what goes inside there.
Putting a cock into a pussy. Thrusting a cock into a pussy. Everything they had done so far had merely imitated that act. The real thing began with the contact between male and female genitals. As she imagined it, Lua's eyes grew increasingly hazy.
“Haa…… haa……♥”
Tap.
“Hiiik!”
Lua, with a dazed look in her eyes, pressed her throbbing glans against Sia's pussy. Sia felt a momentary jolt of pleasure that made her waist tingle, but it was quickly swallowed by surging terror. She had realized exactly what Lua wanted to do. The last bastion of Sia's identity as a man was about to be torn apart by the Grand Duke's massive cock.
“L-Lua. No, Your Highness the Grand Duke!”
“Uuuugh……!”
At her brother's desperate, repeated code word, Lua's reason returned. Even for her, this was an absolute line that must not be crossed. They couldn't let a curse drive them to commit such an act between siblings.
“……Brother.”
“D-Did you come back to your senses?”
“Still, I can't end it like this.”
“Ehh?!”
“You've only made me cum twice.”
“T-That's because you suddenly stopped what you were doing and wasted time doing weird things to my body……!”
Sia was genuinely huffing with anger. Seeing it like the trivial rage of a cute little animal, Lua let out a small chuckle.
“Brother, you're even able to get angry at me now.”
“Ah, s-sorry……”
In an instant, Sia shrank back into her usual timid self. She even seemed to feel guilty for daring to raise her voice at the Grand Duke. The sight was so adorable that Lua didn't scold her for the rudeness. Not that she had been angry in the first place.
“It's fine. You're right, Brother. But I still need to cum one more time.”
“Ugh?!”
It happened in the blink of an eye. Lua forcibly pried open Sia's defiant mouth and shoved her glans all the way down her throat.
“Mmmph?! Uuugh♡ Oohk♡”
“Hngh♥ How dare you defy the Grand Duke, ngh♥ This is your punishment, so take it—ahk♥ It's so good, seriously!”
The tight pressure from her small mouth felt incredible. The heat and wetness inside perfectly enveloped her cock, bringing overwhelming satisfaction. And so the Grand Duke, with no intention of listening to her brother's repentance, thrust her hips until dawn, pumping load after load of cum down her throat.