The main character Shizuki Nakata is suddenly transported into an alternate world.
The world is called Eurupe, and only women exist in it.
With all the males gone, there is a "sacred fountain" that is used, where women bathe and gradually become pregnant.
Having never experienced intercourse, the women of Eurupe are startled at seeing a male genital.
As if possessed by a higher power, the women begin to move their hips with tears in their eyes.

[From DLsite English]