"The heart! "Laotie" is a catchword on the Internet. Laotie is a northeast dialect, which means good friend. The complete meaning of this sentence may be that something touches you very much and causes you to be moved or sad, so it is called "stinging".

Speaking of the origin of "old iron, wear the heart", we have to mention the abstract TV of fighting fish. The audience in this live broadcast room are basically in their teens to twenties and thirties. They are very ostentatious and often send out barrage. One day, a group of children from Northeast China suddenly mixed into the live broadcast room, and many people posted a barrage of "Old Iron, Wear Heart", which quickly became popular on the Internet.