Taimamiko Monogatari

If the exorcist is defeated by a monster… they become the monster’s prey.
They are stripped of their clothes, and the monster uses their exposed skin to steal the source of their power, their spiritual power.
As spiritual power is absorbed particularly easily from mucous membranes, monsters attack the exorcist’s mucous membranes.
Inevitably, the monsters end up tormenting the exorcist’s genitals, buttocks, mouth, etc., leaving not only the exorcist’s body but also their mind in tatters.