A marking, sigil, seal, symbol or tattoo that is commonly placed between the navel and the pelvic region, or on the pubic region itself. Implicitly implying effects on the character to be of magical/supernatural, effecting their arousal, libido or other sexual qualities. It does not, however, explicitly require to be placed on the abdomen/stomach region of a character, and has been adopted to be placed on any body part of a character, as long as it is implied to effect a character's impulses, by glowing or other context.

Distinction from womb_tattoo, which can be misconstrued as an ordinary tattoo located on the stated location on a character's body, as well as nonspecific to the gender of the character.

Name originates from the manga series "Monster Musume", which is currently attributed to establishing and popularizing the term and style.