The word "pubes" is a noun that refers to the hair that grows in the lower part of the abdomen, just above the external genital organs. It is often used to talk about the hair that appears during puberty, which is the time in a person's life when they begin to develop physically and sexually.
In more advanced discussions, you can talk about the cultural or social aspects of body hair, such as grooming choices or personal preferences regarding pubes.
There are no common idioms or phrasal verbs specifically related to "pubes," but you might encounter phrases like "grooming habits" or "body image" in discussions about it.
When discussing topics related to the body, it's important to be respectful and sensitive, as not everyone may feel comfortable talking about such subjects.