What is a metaphor in The Doll's House?

Burning to Tell (Metaphor)

After the Burnell girls receive the doll's house, they are eager to tell the other girls at school. Mansfield writes that "they burned to tell everybody, to describe, to—well—to boast about their doll’s house before the school-bell rang." In this metaphor, "burning to tell" captures the girls' excitement through the use of figurative language. The excitement has a physical presence in the girls' body, as though the desire to share the news is a fire burning within them.