Onsen suppon geisha was part of a Hot Springs series, with Sugimoto having debuted in the first installment in 1971. In this one, she’s so good at using that super-strong vagina of hers that she can fuck guys to death. In the end, she’s pitted against a sexual superman and a showdown ensues. There’s also a subplot about a mad scientist type who needs vaginal juices to create a potion designed to turn Japanese girls black.