The antonyms for the phrase "lay still" can vary based on the context in which the phrase is used. If the phrase is used to instruct someone to remain still, then the antonyms would be synonyms of movements such as "move," "shift," "fidget," "adjust," or "twist." However, if the phrase is used to describe a peaceful state of being, then the antonyms could be words such as "agitated," "restless," "uneasy," "nervous," or "jittery." Depending on the specific situation where the phrase is used, appropriate antonyms can be chosen to convey the opposite meaning.