I gotta admit, chapter 5.2 is disappointing to say the least. Really anti-climatic, and not even all that sexy. Though I guess the dude at least kept his original consciousness, unlike the dude from chapter 4.
Okabe's narrative might be the most interesting one Date's done yet. He focused so hard on "I am Okabe, I haven't been overwritten by Himeno" that it's the only thing he actually retained. She's entirely Himeno, except she's absolutely certain she's actually Okabe, and since she "knows" she hasn't been influenced by Himeno's identity, she rationalizes all of Himeno's behaviors and bad habits as being the influence of Okabe.
The way I interpret it, Okabe was very envious of Himeno initially, and was only a dilligent student because of his mother pressuring him. I'm also quite sure that Himeno wasn't a frequent masturbator (if at all) before Okabe took over. That was likely a form of autogynephilia, something this series largely appeals to.
Base +6, Kraftz +6, otoryuo -6, slug-man +6, vfjTgw +17