2. Source: A friendship between lips and teeth comes from the ninth episode of the second season of Have you eaten? In the conversation of Gao Jiacheng, the host, he often dreamed of "dogs" when he was a child, but in the book Duke of Zhou, the dog appearing in the dream means "the disaster of your tongue". The host Zhao Yingnan made a slip of the tongue, mistaking "the disaster of your tongue" for "the friendship of your tongue". Due to possible ambiguity, the scene was once very chaotic.
3. Usage: He and I often spray each other online, which is regarded as verbal communication.