Translated from original post:

A town girl endlessly milks an elf who can continue to ejaculate as long as he still has magic.
Elves ejaculate by converting magical power into semen, so their semen contains a large concentration of magic and fetches a very high price. It's also said that if you take that into your body, you can gain magical power otherwise impossible for mere humans.
These girls who absorbed a large amount of semen through their skin, mouths and vaginas became known as the golden witch sisters, and became fabulously wealthy