butterfly words (p. 45)
On page 45, words are depicted as if they are "butterflies." This is a metaphor of language in an ideal state, in which words are not rigid concepts that dominate the thing they are supposed to represent. Instead, language would ideally help express something which could be entirely pinned down by the word used to express it. See the Themes section of this Note for Lawrence's attitude on language.
leaves of a life (p. 50)
On page 50, words are depicted as "dead leaves," contrasted to "leafy words of an effective life." This is an extended metaphor which likens life to a tree, and the leaves of that tree to the expression of that life. By using a naturally growing object to describe man's life, the novel points to the necessary, instinctual forces that keep a life healthy, such as the sexual instinct.
"Clifford was very much a poodle showing off" (p. 73)
This metaphor likens Clifford to a poodle, a very unnatural animal which is tamed by man. This represents his artificial nature.
"Imagine if we floated like tobacco smoke!" (p. 75)
With this simile, Constance responds to the idea that man without a body would live in a higher state of evolution. The intellectuals around her think of the body as something to be ashamed of, and the mind as the only worthy element of man. However, Lawrence wants to express how necessary the body is for man. By comparing man's life without a body to tobacco smoke, he is implying that it would be a disgusting existence without a body.
the penis and the belly (p. 37)
Tommy Dukes, one of Clifford's intellectual friends, articulates the idea that the mental life needs to have some sort of attachment to the body. He uses the "penis and the belly" as metonymical metaphors for the lower instincts of mankind that are associated with the body.