Yuuki Anzai arrives at ONL early the next morning. He's cautiously optimistic (mostly cautious) about the safety of what they're going to try to do and a little ashamed he arrived so early. Midori Anzai and Tsukasa Taira invite him up and Midori introduces them to some of the staff including Kurasawa from R&D, Julius Kurtz, and Dr. Kitashiba, who will be the doctor in charge of monitoring their sexual interaction.
Then, she has Kurasawa show off all of the restraining devices that they can use. There are nail protectors made out of a soft material like silicon that also leave the finger pads exposed, so the devil can feel their partner better. Next is an eye mask with glass that can change transparencycccccccc from completely transparent to completely opaque. There are also masks that go over the mouth - a wire model and a gas mask model - that also inhibit the scent receptors. Yuuki inquires about something to heavily restrain his movement and Midori shows him something called a "Jail". It is a large pen with strong belts attached to the walls and corners. Kurtz and Kurasawa are asked to demonstrate by playing the devil and human respectively. Midori helps attach the belts to cuffs on Kurtz' wrists and ankles, and to a vest with anchor points on his chest and lower back. The belts are designed to lock in place if they are tugged too hard, like the seat-belts in cars. Kurasawa then demonstrates that the belts can be controlled by voice commands to restrict or release Kurtz (and a remote control held by the doctor can do the same). Since Yuuki's temperature reading ring is going through maintenance, Midori gives him and Tsukasa an earpiece to measure temperature. The last thing about the Jail is that the floor can slide for easy "insertion" which is demonstrated tactlessly by Kurasawa and a less-than-enthusiastic Kurtz. Midori brings up how the air between Yuuki and Tsukasa has been a bit off since the morning, so she tells them to go somewhere to talk in private.
Tsuaksa asks what's bothering him up on the roof. She thinks it may be the same thing on her mind. She remembers back to the night before during Midori's sex talk. She explained that during the last half of the encounter, the human would have to take the lead, since the devil will have lost his senses. Since that's the case, the first half should be more catered to what the devil wants. She inquires bluntly about Tsukasa's sexual experience and Tsukasa inadvertently answers that she doesn't even masturbate. Midori recommends coming up with a procedure of what both parties want out of the encounter and she provides a chart as an example. The chart is a timeline with different sexual acts each partner should to to the other along with what restraints they would like applied when. It also plots estimations of what stage of transformation the devil would be at and when to tranquilize. She reveals the chart is the one she and Tamaki Anzai used to Tsukasa's complete shock. She continues to go into more detail about what they tried to do, but sadly weren't able to do. They had wanted to try the cowgirl position, but it was too difficult. She recommends Tsukasa stick to the missionary position. However, since it's her first time, she will most likely bleed.
Back on the roof, Tsukasa tells Yuuki she might bleed and it seems she hit the nail on the head. Yuuki was worried about that. She assures him that they'll be safe with all of the equipment they can use and all of the people around them. Yuuki still doesn't want her to bleed, because that means it will hurt. Tsukasa is touched by how concerned he is about her and she wants to be closer to him. She asks for a kiss and he gives her one before they head back down.
Their second sexual intercourse attempt begins. Tsukasa waits for Yuuki on the bed of the Jail. Dr. Kitashiba watches her monitors behind a two-way mirror. Tsukasa still has a million thoughts in her head from her lecture with Midori. And the condom she was given is still, embarrassingly, in her pocket. Yuuki enters with a button up shirt on (so he can take it off in the restraints) and Tsukasa helps to buckle him in. Tsukasa remembers back to what Midori said and asks if Yuuki wants to touch her boobs. Yuuki instead asks her what she wants and she nervously asks for a massage after another flashback to Midori sharing way too much about her kinks. The massage starts to get sensual and Yuuki's eyes start turning red. He asks for the face mask, but gives her a kiss before she puts it on. Yuuki's tongue can still reach past the wires of the mask, so he licks her neck and starts taking her top off and touching her breasts. When Tsukasa asks him to lick them, he really starts to transform as he does. Tsukasa sees him struggling to keep a hold of himself. He nearly reaches his breaking point when his fingers accidentally trace the scar on her arm he made when he bit her, but Tsukasa tells him not to be angry at himself for that. Yuuki explains that he can't forgive himself for what he's done. Tsukasa says she'll always forgive him and he shouldn't bottle his emotions up. With that, Yuuki manages to stabilize his transformation. He quickly motions for Tsukasa to keep quiet about it and she helps him get the eye mask. Dr. Kitashiba notices the drops of his levels, but assumes there is a fault in the equipment and decides to monitor with eye contact instead. Tsukasa makes the mask opaque. Yuuki tells her he won't be stable for long. While it lasts, they hope to make the most of it.
- Midori gives Tsukasa a devil sex talk, mostly drawing from personal experience.
- Midori introduces the staff and all of the restraining devices to Yuuki and Tsukasa.
- Tsukasa and Yuuki start their sexual intercourse attempt with some foreplay.
- Tsukasa prevents Yuuki from losing his senses when she notices his anger at himself.
- Yuuki's transformation stabilizes and they hide the fact from the doctor monitoring them.