I wonder what their label is?
Sex friends? It doesn't look like they're just in to bang
Live-in partners? One is (assumably) a minor, so it would be a crime.
Considering they're consensual about their "activities" but not entirely romantically attracted to each other.
They're like married couple, actually. Exact dynamic for couple with age difference. Their age gap wouldn't be too crazy 10 years from now, but boy, as of now, it's still a crime for Kazama. (She's in grade 11 right now, so, hardly be 18; she's likely to still be 17.)
Also, I feel that their sex is stale for me for a while; but man, I might share the same taste as Kazama. Yukata is really something. (And as soon as Akane change back to her usual cloth, all the heat is just gone

)