Why are there "vests" in many screen names?

Trumpet is a number other than the main number ~

Vest is a kind of clothes, sleeveless ~

The waistcoat expands into a small size, which comes from this joke:

A tiger chased a snake and the snake fell into the river. Soon a turtle came out. The tiger grabbed the turtle and said, don't think I don't know you when I put on my vest! "

XX vest is someone's trumpet,

Some people's main name is XX vest ~

Tianya also has a vest.

It was the time when Tianya registered for money, and good-hearted netizens registered for public use ~

It is also used to send something more personal.