What does it mean to have a fire behind Tik Tok's friends chatting?

There is a fire behind Tik Tok's friends chatting, which means chatting with each other. Chat box fire represents a kind of relationship between oneself and the other party, and it will be given a sign of fire by Tik Tok, which is also a sign that two people are very close. If you don't talk for a long time, the fire will be gone.