聖乳の巫女お姉ちゃん瑠璃 ～癒しの母乳で中出し生活～

The lead character has a childhood friend who has become a shrine maiden.
One day, he is put to the test to marry her and receives a curse of death.
It turns out that only her milk has the power to cancel it.
And this is how his love life with her, healed by her breasts and milk.

[From English DLSite]