- Type: Activity / Contextual
- Description: Sex between family relatives, even those not related by blood.
- Note: Is required for the aunt, brother, cousin, daughter, father, granddaughter, grandfather, grandmother, inseki, mother, niece, sister, and uncle tags.
- For non-parody works the proof required for this tag must be contained within the gallery's contents.
- For parody works generally only the mainline canon is valid (see the discussion page).