C132 Dream is born from the heart

Holding the Underworld's performance phone, I repeatedly read the contents of the text messages. This live broadcast had a fundamental change compared to the previous ones.

"Use Tong Mulberry Symbol to enter Huang Xue's dream? Do you want to have a live broadcast of your dreams? " I don't understand the meaning behind the Underworld's show, nor do I know how to use Tong Mulberry Symbol