Antonyms for the phrase "laying on thick" include the terms "subtle", "restrained", and "low-key". When someone is being subtle, they are usually reserved in their communication and do not exaggerate or overstate their opinions or emotions. When someone is restrained, they are being cautious in their expressions and are not overly enthusiastic or melodramatic. Similarly, when someone is being low-key, they are being discreet and understated in their demeanor and actions. All of these antonyms suggest a more measured and balanced approach to communication and interaction, rather than a bombastic or overblown one.