What do you mean, like a deer to the forest, like a boat to the shore?

It means that a person returns to his familiar, safe and comfortable environment or state.

This sentence can be understood as, just like the deer returning to the forest and the boat returning to the port, a person will feel quiet and at ease when he returns to his familiar and favorite environment.

It emphasizes that individuals can find a sense of belonging and security in familiar environments, and its synonyms can also include similar figurative expressions such as "going home like a swallow" and "being like a duck to water".