Tie hair: refers to a boy around 15 years old.

Girls with hairpins: refers to girls around 15 years old.

The ancients did not cut hair or shave their heads. When children were very young, they let their hair grow as long as they wanted, which was called "hairy boy." This is where the modern term "hairy boy" comes from. In childhood, the hair is very long and needs to be tied together into a bun or braid. It looks like the "horns" on the heads of cattle and sheep, so it is called "total horns". After entering puberty, boys have to tie up their hair and fix it with hairpins, which is called "hairpin". Girls also have to tie up their hair, but the hairpin is different, which is a "pin", so it is called "jizizi".