I think I have read this hentai! This is where the old fat flasher suddenly appears again and convinces her to be ok with men through more orthodox means, making all his efforts null-and-void because not raping people is considered "beta" behaviour, right?
Jokes aside, it was cute. Reminds me of that ookami (or whatever its name was) manga, where entire plot was mc tried to crossdress to get closer to his library-crush