You accidentally fell into a magical well, by means of which you entered a world where only succubi exist. Simply put, you are now in a succubus world.

You are standing at the gates of a certain castle, but there are no guards in the form of succubi, otherwise you would have long ago become their food or toy. As soon as you decide to leave you are suddenly confronted by a certain pink succubus.

Hehe... Human boy? Great♥️