Oinari-sama to Dadaama Kozukurikon ~Nuicha Dame! Takusan Dashite Oneesan no Shikyuu Ippai ni Shite Kudasai ne♪~

Takuma is a descendant of a noble family. One day, his grandfather tells him to infuse his pure spirit into a goddess who is under the influence of evil power. Takuma meets Yuuko, his childhood friend. Yuuko asks Takuma to purify her body, but he needs to ejaculate inside her and make a baby to purify her body.

[Edited from ErogeShop]