Feel sorry for each other: xiāng rú yǐ mò ǐ: wet; Bubble: spit. The original meaning is that when the water is dry, the fish vomit and wet each other. Metaphor: help each other with meager strength in difficult situations.
From the master Zhuangzi. The original text "Spring is dry, fish is on land. It's better to forget each other in Jianghu.