Made a Slave: Played for laughs, it's what Risa would like to think Kagami is to her.
Nice Guy: Even though Risa doesn't deserve it, he's this to everyone.
Oblivious to Love: Unlike most harem protagonists, he's not like this entirely, he seems to be mildly aware of the affection the girls have for him, except with Ayana-sensei, who had to spell it out for him, not that he's commented on it since.
Unlucky Everydude: As is the standard for harem protagonists. Poor guy can't seem to catch a break.
Wholesome Crossdresser: His cute appeal is played up when he crossdresses, to the point that he will cause straight males out-of-universe to question their sexuality and punch a bodybuilder for one night with Kagami.
Ambiguously Lesbian: Risa has been shown to dislike men, Kagami confirmed she hates them, and her initial interactions with Ayana-sensei were...pleasing to say the least.
Bi the Way: She seems willing to shelve this for Kagami though, however, she seems to prefer his crossdressed state to his normal appearance.
Clingy Jealous Girl: And it's done so it's adorable, not even yandere-like. Ayana is earnest about her desire to get affection from Kagami, and gets jealous easily when she pays more attention to the other girls. Since she lives with him, she doesn't hesitate to press her advances.
Fetish Fuel Station Attendant: A Tall, Purple-Haired and Bishojo Hot Teacher with large tits and a healthy dose of Baby Got Back; who manages to get into innumerable fanservicey situations and seems to have a fetish for anything involving her ass.
First Name Basis: She and Kagami are on first name basis, albeit with the "-san" and "-sensei" honorofics.
Immodest Orgasm: Quite a few times actually, but the most obvious example was when she had Kagami take her temperature through a thermometer in her butt, it seemed to be a bit too much for her and she screamed "I'M CUMMING!". Explains the Seinen rating to a degree.
Sensei-chan: Ayana is most definitely this, however, it's done to a degree that you sometimes forget she's a sensei and could very well be a student. Kind of helps, since her main goal, aside from keeping Kagami safe, is obviously to bone him.