i believe the story start with our protagonist ( highschool girl) seeing a monster ( tentacle slime likes ) hypnotize or dragging and R some women in mall/ train station the monster realizes that someone can see him so he targets those women (MC) , she study about the monster and turns out her mother is an exorcist (Japanese type yokai exorcist) and that monster is usually their enemy so her mom teach her by giving her some statue, at night that statue turn into some kind of angle/god and want to give a power to that women by f ing her, next day she battle that tentacle monster she won and that monster turn into a man
the art is very good, proportional not extremely large tits I been looking on monster or tentacle tags and I couldn't find it at this point I believe that doujin is deleted or something lmao.