What do you mean by childhood friends? What are the allusions?

Childhood friends are an idiom, which is interpreted as:

Plum: green plum; Bamboo Horse: Children ride horses with bamboo poles. Describe how naive children play games. Now it refers to the intimate relationship between men and women when they were young, childish personality, pure feelings and long-term profundity …

Source:/Cheng Yu _ Search.asp.

Childhood friends come from Li Bai's ancient poem Long March.

Li Bai, a great poet in the Tang Dynasty, wrote a five-character ancient poem "Long March", which describes a woman who is eager to travel hundreds of miles from her residence to see her husband in a long sandstorm. At the beginning of the poem, I recalled their intimate play together since childhood: "When you, my lover, rode a bamboo horse, trotted around in circles and threw your childhood, we lived together in an alley in Changgan, and we were all young and happy."