In girls' interpersonal relationships, there are three kinds, one is that they can meet without washing their hair, the other is that they can meet after washing their hair, and the third is that they don't want to meet after washing their hair. Friendship without shampooing literally means meeting without shampooing, which is usually used between girls. If two girls have a good relationship, the other girl can go out to see you without washing her hair. Why can you test the friendship between two girls without washing your hair?
Girls love beauty and dressing up, but they are sloppy at home and don't pay too much attention to their image. But make up, comb your hair and match your clothes before you go out. It's really beautiful after dressing up, but it takes a long time and a lot of thought. Therefore, it doesn't matter if you don't wash your hair or put on makeup in front of your girlfriends who have nothing to talk about and have nothing to reveal, and showing your ugly and sloppy side will not be rejected.
Shampooing is of special significance in communication with people, especially for girls. If a friend is willing to meet you without washing his hair, and you don't mind, then your relationship is really good. Similarly, this applies to the "basic feelings" between boys. If you don't wash your hair, your hair is unkempt in front of your friends, and your friends don't mind, then you are a pretty good gay friends.
If you want to meet a boy or boyfriend you like or a girl or boyfriend you like, of course, you have to "wash your hair" before you can meet. So later, a stalk with similar meaning such as "no makeup" was born.