As a rule, it is used by everyone in relation to the younger or lower in the social sense, with which there are close relationships, to people you know from childhood. It is usually used when addressing adults to children and women within the family, small children to each other (for example: onii-Chan-brother), girlfriends to each other, guys to their favorite girls, just as an expression of affection between very close adults. It can be used in relation to a grandmother or grandfather, corresponding to the Russian diminutive "Granny" and "grandpa".
