Love Divination Skull is one of the magical items described in Monster Girl Encyclopedia World Guide III: Sabbath Grimoire.
Guide Book Entry
An unusual magical tool that begins to speak when you hold it in your arms and turn it towards your face, reads the heart of the person holding the skull, and correctly guesses the target of one's favor. It was popular a little while ago among the children of the monster realm who love stories of sensual love, although the appearance is easily preferred by children of mamono, it is naturally not the real thing but a decoration.
Continuing to hold it as is, rather than saying the name of the person you like, it possesses a bad habit of beginning to chatter on about things like "What kind of place they like", "Why you like them", "What do you want to become with them".
Until this point, it only speaks in the mind that is read, but if you continue to hold it, the skull's "Delusions" begin to enter the conversation, becoming extreme content such as "I will look at that person with an indecent eye", "When I look at that person I will want to eat them and drool", "I want to join with that person until I become messed up with his semen" etc. And yet, there is no complete lie in the words the skull speaks, they are thoroughly based on content taken from the heart of the person holding it. However, it reads not only the contents of what you are thinking in your head, but also the desires dwelling in instinct, and they are exaggerated to the maximum obscene content based on the values of mamono.
Also, although this skull is weak, it holds a hint of power towards the one holding the skull. The lewd delusions the skull talks about are based on reading the mind, although in the beginning it is denied that they would think such things, as they hear it they begin to realize that it exaggerated their true intention, before long they feel that it is what they truly desire. It has a particularly immediate effect on human women who are not as resistant to obscene thoughts compared to mamono, a human woman who holds the skull will start to blush and be embarrassed, eventually seeing how the skull is stained.
As a children's toy, it is a magical tool with too much power. For that reason, a game called "Pretend Extremist" where you capture a female soldier of the Order and have her continue to hold the skull against her will, becoming a "Demon" that captures heroes and administers lewd torture and breaking, for a period of time was a fad among mischievous mamono children, and became a problem.