I've noticed a few people saying this should be tagged as Hentai. It's pretty dang close, but I'm going by MangaDex's definition of what qualifies as H and what does not.
Per MangaDex's rules:
"Tag porn (and only porn) as hentai. Ecchi and smut do not count. The primary focus must be on the sex, and genitals must be visible (typical censorship aside).
Oversimplified rule of thumb: if it's mostly porn with some plot, it's probably hentai; if it's mostly plot with some porn, it's probably not."
I think this one falls into the Ecchi/smut category. It's mostly plot (however lame the plot may be) with some porn. The primary focus is not on the sex and genitals are not visible (no censorship required).