Breast milk is the first nourishment, so dream books read it as care given and received, deep bonds and the wish to nurture or to be nurtured.
When this appeared in your dream, what were you feeling?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.