ato's 5th film as a director is a rather obvious product of a time when Nikkatsu started to feel threatened by the rise of hardcore AV pornography and its easy availability for home viewing via the spread of VHS into pretty much every home. As a result, they got a whole bunch of pinku directors to try making something as close as possible to AV porn as they could get without resorting to outright graphic hardcore pornography. Cf. Masaru Konuma's WOMAN IN A BOX or the entire output of the "Go Ijuin" collective (ZA IKENIE, ZA S&M, ZA MANIA, ZA GOUMON et cetera). UNIFORM VIRGIN is Sato's appoximation of an AV flick. It's not among my favorite films of his.

Overview from themoviedb.org