In almost all societies, the usage of avoidance is observed to maintain incest taboo. A father-in-law should avoid his daughter-in-law; similarly a mother-in-law maintains avoidance relation to her son-in-law. It is also observed in the relationship between husband’s elder brother and younger brother’s wife. It accounts for the Hindu purdah (curtain) system.
Joking relationship forms the reverse type of usage to the former. The relationship between husband’s younger brother and elder brother’s wife and also between elder sister’s husband and wife’s younger sister, as found among the Hindus, and the tribals, may be termed as joking relationship. All kinds of jokes, including the vulgar sexual jokes, are permissible among the above-mentioned kins according to traditional social norm.
The maternal uncle (mama) is given an important status so far his relation with his nephew and niece are concerned. The Nayars of South India exhibit avunculate kinship usages.