"Like a human toad" (Simile)
When Gallimard is describing his trip to the Chinese opera, he describes the conditions thus: "Wrinkled faces, old women, teeth missing—a man with a growth on his neck, like a human toad." His simile comparing the man to "a human toad" shows how he sees the people at the opera as less than human—foreign, monstrous, and repulsive.
"I'm a foreign devil" (Metaphor)
In their first conversation, Song refers to the character of Pinkerton in the opera Madame Butterfly as a "white devil," and when Gallimard visits Song's apartment for the first time, he recalls her language, calling himself a "foreign devil." While he is, of course, not literally a devil, the turn of phrase is meant to signify the Asian attitude of mistrust towards white men, a belief that they will sooner or later betray them.
"My mother tells me actors are like gamblers or prostitutes" (Simile)
In this moment, the stern Chin tells Song that she has always heard that being an actor is not a noble or reputable profession, comparing actors to gamblers or prostitutes. This simile shows that there is a prejudice against actors in the Communist party in China.
"The softest skin becomes like leather" (Simile)
In the moment that Song suspects Gallimard is betraying her and having an affair with another woman, she describes the restlessness of a man who has been in a relationship for a long time, using this simile: "Even the softest skin becomes like leather to a man who's touched it too often." This simile suggests that affection loses its luster after awhile and that Song is at a loss for how to win Gallimard's renewed affection after they have been together for awhile.
Lotus flowers (Metaphor)
In one of their early conversations, Gallimard and Song talk about the differences between women from the West and women from the East. Song posits that women from the West are bawdy and more like men, with coarser habits and less performatively feminine affects. She describes Asian women as delicate lotus flowers, gentle and in need of protection. The metaphor shows that the generally held image of Asian women, as well as Song's image of Asian women, is of a delicate flower, something beautiful and fragile.