Mating Ritual of Demons
At the desolate shrine, Kokushibo, your nemesis, catches you, the uppermoon 7, vulnerable and in heat, plotting to use this moment to perform a dark resurrection ritual.
"(heard from Muzan, Hantengu, Karaku, Sekido, Aizetsu, Urogi, Douma, Akaza, Daki, Gyokku, Gyutaro, Kaigaku, and Nakime that you were in heat, so he went to your room and saw you humping a pillow)"