It has been pointed out to me that this story is too Mature for FFN. I do not wish to be out of compliance with FFN's rules of use. So, please look to archiveofourown for the continuation of this story.
Here is an excerpt of the Chapter 2 from what is over at AO3:
Yue listened to Hajime carefully. At first, she thought it must be some kind of elaborate joke, but he was so serious about what he was telling her that she dismissed that idea. He explained how some people actually wanted to be bound and disciplined as a form of sensual recreation. They claimed to feel an intensely euphoric release unlike anything else – either while they were bound or at the moment they were released.
...the moment they were released.
Those words had a severe impact on Yue. Several hundred years of tortuous imprisonment embedded in that cube, deep in the Orcus Labyrinth had never once been enjoyable. But the release… When Hajime was doing everything he could to set her free. Yes, that had been a most remarkable experience, indeed. I could tell from his smell that he was but a mortal human, but he looked like a god to me. When I was released, I could barely speak. Part of it was from weakness, but mostly it was from the euphoria of release. Perhaps… there is something to this after all. However, I see a flaw in his plan.
"Hajime, do you intend to tie her up?" Yue asked in her characteristic, emotionally flat tone.
"Yes, in the story they used a variety of bindings. Rope, leather, and even metal binders are used in this kind of play, but I think rope would be best." Hajime replied.
"I don't think that will work." Yue shifted her gaze across to Tio and explained, "She's too strong. I don't believe there is any rope in the world that would hold her."
"The object isn't to immobilize the submissive… but I see your point." Hajime thought about it and came up with a solution. "The rope's strength will be irrelevant if I use it as a metaphor."
"Hmm?" Yue cocked her head. She understood the words, but not the meaning behind them.
"Will you help… or would you rather that I do this alone?" Hajime asked his diminutive lover.
"Wouldn't my presence be distressing for Tio? Yue asked.
"I'm counting on that." Hajime concentrated on his ring until a glowing circle opened and revealed a coil of silky rope that looked like it had been spun by magically enhanced spiders. The rope was strong and quite valuable, but Yue was right. It wasn't nearly strong enough to restrain Tio, so it would be a shame if the dragon girl ended up breaking it.
"You're a meanie, Hajime." Yue responded.
"No I'm not. If you don't want to be there, I won't ask you to." Hajime said softly.
"I meant that you are being mean to Tio." Yue clarified what she had meant.
"Oh that." Hajime felt a bit of relief. He didn't like it when he disappointed Yue, but this was only a misunderstanding, "For a masochist like her, the fact that someone is watching her being disciplined will probably increase her enjoyment.
"… She is a pervert after all." Yue wanted to challenge what Hajime said, but she couldn't. Instead, she asked, "Is that the only reason why you want me there?"
"No. One of the things that the manga… story taught me was the importance of safety. Since she will have to voluntarily lose all control of her body, and give that responsibility to me… it would be inexcusable for me to let her get hurt at my hands." Hajime had a lot of confidence when he went into a fight against a monster… but he had done that sort of thing hundreds of times now. This would be something new and… "It would make me feel better if you were with me in case there is a problem."
"Shea and I will both be there." Yue decided. Of course, it was a promise that would be easy to keep. It would be unlikely that Shea would just wait patiently while the three of them went off to do something sensual… even if it was perverted.