Seiso Bitch na Miko Senpai

In a village deep in the mountains, there's a traditional ritual to determine the successor of the priestess. When the priestess turns eighteen, an eligible bachelor among the men in the village is chosen to become her husband... in other words a seed bearer.

Taiki becomes that seed bearer to the current priestess who turns out to be his upperclassman, Misaki Amagawa. Long has he been infatuated with her but now they are together by fate. Whether it's in the shrine or at school, their desires are no longer in check as Misaki longs for Taiki's seed.

(Source: Denpasoft)