These are from a company called Soft On Demand, Japan's most famous (and creative) adult movie producers. They do all sorts of crazy stuff, as the story goes they celebrated their first day of being in business by putting a pair of an actor and actress in a clear plastic box suspended over a busy intersection and had them have sex (with hidden cameras filming them from afar) until the police stopped them.
The guy in charge of SOD is rather famous in Japan as well, because he's been arrested more than a few times for the antics his film crews do.
Anyway, a signature series they do is called the Zenra -- Stark Naked -- series. Full of cute girls (usually lots of them) who want to break into modeling or movie careers, doing somewhat normal things -- like basketball, playing around some hotsprings in the snow, going on a bus tour of Japan, etc -- all while completely stark naked. Their latest adventure was to find a bunch of wannabe starlets who could play instruments, train them up to an actual acceptable level, and SOD held a stark naked orchestra -- they even sold tickets.
ER, anyway. In the movie this comes from, the owner of the company sent a few of the girls to intern at the soft on demand offices -- in the nude, of course -- without warning the guys in the office beforehand.
I like the sister version of this movie, where they send a bunch of horny Soft on Demand fans into the offices to torment the (rather attractive) female office ladies who work there. "Sure, you can have your briefcase, we'll trade it for your pants," that kinda stuff.