I like Kanokon for the fact that while it's the least believable harem animu ever, it's the most like a...what's the word...harem!
This kid knows that Chizuru wants his dick, and he's not sure why, but he's going along with it when his hand is forced. He doesn't want to be raped in the middle of a street, but if the mood is right and they're alone, he's down for the kinky shit.
This second bitch is just down with the fact that he saw her, knew what she was, and didn't get all "No, I'm saving myself for the girl who's trying to molest me, you crazy wolf bitch!" He treats her like just what she is; a friend he's not really into, but isn't blowing off either.
The only Tsundere-like character in the manga is the Class Rep, who isn't necessarily Tsuntsun at all because she doesn't act harsh towards him, just the bitches that are doing "inapproriate things" to the guy she wants to blow. A typical harem Tsundere would've hit the main character at least once by the fourth episode.
All of these closet shotacons all want to find themselves getting poked by this unassuming pimp muthafucka, and what sticks this apart from the regular harem scenario is that he's not doing anything to fuck up the delicate balance. Way to go, Kouta.