Why is the little girl unhappy when she calls her brother?

This is a very interesting question. The phrase "little brother" is a psychological scene preset by both sides.

First, from the girl's point of view, showing weakness and seeking the protection of boys is an obvious coquetry. If you add some shy expressions and body movements, it will make boys' desire for protection explode.

Second, from a boy's point of view, being called "little brother" by a petite girl will first make people feel that this girl is very kind, unprepared for herself and involuntarily wants to take care of her. What if I call my brother? It wouldn't have this effect. Adding the word "small" gives people the impression that they are more intimate, less formal, more intimate, even more ambiguous and provocative than brothers.

You can imagine, when a girl in MengMeng calls you "little brother" softly, will it make you feel uneasy, happy and loving?