Released on April 21, 2021, Waters of Fertility is a pixel art hentai simulation game where the player becomes the god of fertilization and has to use their powers of possession (NTR (you don't have to do NTR)) to control the inhabitants of the onsen to have sex and create children. The game features 48 different sex techniques (sex animations) to spice up and vary gameplay. The controls and gameplay are unique to this specific experience, but it's easy to play. It functions as an arcade game-score system, but no technical operations are required.
Below is a website with further information.
The gameplay is somewhat similar to that of the game Summer Memories, but without the strange kid looking MC having sex with older women. In this game, everyone is and looks like an adult and is of age.
https://lewdzone.com/game/yukiya-onsen-the-waters-of-fertility/