[Studio Q (Natsuka Q-ya)] UI×YUI! (K-ON!) [Digital]

Incest (近親相姦) refers to sexual content between family members. In doujinshi, this commonly involves siblings, parent-child relationships, or other familial pairings. The tag covers both blood-related and step-family scenarios. It's one of the most common narrative frameworks in doujinshi, often used to create dramatic tension or taboo appeal. Related tags include 'sister,' 'brother,' 'mother,' and 'father.'

Futanari (ふたなり) refers to characters with both male and female sexual characteristics — typically female-presenting characters with a penis. This is a significant genre in hentai with its own dedicated audience. The tag covers a wide range from characters with both sets of genitalia to characters who are essentially female with male genitalia. Artistic treatment varies from realistic to highly stylized. Related tags include 'males only' (for futanari-only content) and 'yuri.'

Sister (姉妹/お姉さん) refers to content featuring sister characters. This tag covers both older sisters (ane) and younger sisters (imouto). It's commonly paired with 'incest' for blood-related scenarios or can stand alone for step-sister or non-related sister figures. The tag is one of the most common character relationship tags in doujinshi.