Sticking one lip out is a nonverbal expression of displeasure or annoyance, often used by children. However, there are several antonyms that can be used to convey positive emotions.
One antonym is smiling, which is a facial expression that conveys happiness, contentment, and friendliness. Another is grinning, which is a broader smile that conveys amusement and satisfaction. Additionally, smirking is an antonym that means to smile in a self-satisfied, or conceited way.
Other antonyms for sticking one lip out could be laughing, beaming, or even refraining from expressing negative emotions altogether. These positive expressions and attitudes can help promote communication, empathy, and positivity in our interactions with others.