The phrase "most smothering" implies a sense of suffocation or excessive control. Some antonyms for this phrase may include "liberating", "empowering", "unburdening", "relaxed", "spacious", and "light". These words suggest a sense of freedom or letting go, rather than feeling constricted or oppressed. Other antonyms might include "open", "unrestricted", "limitless", "expansive", or "welcoming" - each expressing a sense of openness or possibility. Ultimately, the choice of antonym will depend on the context in which the word is being used, as well as the writer's intended meaning.