Didn't expect "the rear man" title to be, well, literally that. XD
Also, as a married woman, I say that scene was sexy as f***. She had resolved not to know, and he knew she did not know. There was definitely fear, but it was definitely not an uncontrolled rape situation. I mean, we know that Koharu is more than capable of fighting back when Ryuu pushes her too far, right? All those past episodes where she denies him sugar, slaps him for being ecchi, threatens to shove vibrators up his a**... Long story short, smut happened because she was totally in for the ride. (The whole story has been about her struggling to do things her way and feeling miserable, then Ryuu comes in and smashes every preconception she had, anyway... right?)
Side note though: "boink" as a sfx during an intense sex scene is just hilarious. PLEASE DON'T. I can't deal. Seriously xD
Side note two: that look on Ryuu's face after it was over, and what he decided not to say when he left... Aaaaaaaaaa the feels! So conflicted!!
Side note three: wifey #1 definitely knows something haha.
Minor side note one: Did he just bonk wife #2 when it was supposed to be wife #1's turn with him??
Minor side note two (ok I get it last one I promise): I'll bet you anything the passcode is something Koharu DEFINITELY knows, from a history they shared together. Which ties down with Side Note Two... (Yup, I'm a conspiracy theorist. So shoot me.)