How does the author use metaphor in the novel, The Testaments: The Sequel to The Handmaid’s Tale?

One example of metaphor in the novel can be found in the way the Aunts refer to them as "precious flowers" - which, for the Aunts, is a metaphor to scare them into seeing their bodies and their virginity as sacred: "we were precious flowers that had to be kept safely inside glass houses, or else we would be ambushed and our petals would be torn off and our treasure would be stolen..." (10).