Taboo.
Panīaw unta mi'yibun hinan agi.
(It) is taboo for one to sit with his sister.
Taboos are extensive, governing many aspects of everyday life. For example, it is taboo to do or say something classed as offensive, līhog; to eat vegetables with meat offered in sacrifice during the time of harvest; for a man to sleep with his wife or have sexual contact with her for a period of a month following the sponsoring of a headhunting enactment ritual, bahbah, or a ceremony at his house for a person killed violently, bināgung, or during the drying period, about two weeks, of the family's newly-harvested rice; for a ritualist, mumbā'i, to bathe, eat vegetables, sleep with his spouse after various kinds of ritual prayers.