A metaphor example: That boy is a thorn in my side. The main object is the boy and the comparison is thorn. The meaning is the boy is so annoying.
The next example is: That boy has ants in his pants. The main object is the boy. The boy is being compared to ants. The meaning is the boy can't be still.
The next example is: That boy has ants in his pants. The main object is the boy. The boy is being compared to ants. The meaning is the boy can't be still.
LI: to describe things by metaphor.