So in the end, everything that happened was kind of pointless. It was just erotica for erotica's sake. Touka didn't get what she wanted because she's extremely stupid and Shirasawa didn't find out that it wasn't Kaho because he's too horny for Kaho. It seems to me that the author really just wanted to masterbait, I mean, to set up a master bait in order to make us believe that something relevant to the plot would happen. The real reason why Touka hates Kaho remains a mystery.
Thanks for the chapter!