柠檬比你好酸口不酸心
[níng méng bĭ nĭ hăo suān kŏu bù suān xīn]
This username combines playful exaggeration and wordplay, suggesting someone who is sarcastically 'sour' like a lemon but not truly bitter at heart. 'Sour mouth not sour heart' implies that the user may come across as sarcastic or tough, but they are kind-hearted.