柠檬加醋心好酸
[níng méng jiā cù xīn hăo suān]
This title translates as 'Lemon and Vinegar My Heart Is Sour'. It refers to a state of extreme sourness in feeling as if adding vinegar to already sour lemon. Usually, it describes the bitterness and jealousy one feels inside over situations like losing someone loved, failed attempts, etc.