Wishing Well that Talks - Futanari TF (Patreon)

There was an urban legend that the boarded-up well on top of the hiking hill in Moonvale was capable of granting wishes. 

It was the original idea of Aurelia the Elf who once established this city thousands of years ago; She had captured a genie and bound it to the well where denizens of her town could go and ask for simple wishes. It was initially a convenience. But, when the humans took over after the end of the era of elves, the first king ran into problems controlling the mischievous genie.

The genies started twisting people's wishes and the king finally had to close the well for good. Hundreds of years later, now in the city with rapid urbanization, in the age of science, the well was all but forgotten. Recently uncovered by college students on a hike, this legend has started to spread among the younglings of the city.

Despite it's mischevious nature, the genie does grant some wishes sufficiently.