“嘴” means “mouth,” and “瓢,” which literally refers to “a gourd dipper,” can mean “uneven” and “crooked.” In northern Chinese dialect, to say someone has a “crooked mouth” implies that the person talks nonsense, is loudmouthed or has a slip of the tongue.
Nǐ huìbuhuì yǒushíhòu shuōcuòhuà？
Do you sometimes say the wrong words?
Dāngrán huì。Zuótiān xiàwǔ wǒ nánpéngyou kàn zúqiú bǐsài， cóng bīngxiāng lǐ náchū yīguàn píjiǔ，wǒ rěnbuzhù shuō tā，jiéguǒ jiù zuǐpiáo le。Wǒ shuō ：“wèishénme kànjiǔ shí yīdìng yào hēqiú ne？”
Of course I do. Yesterday afternoon, when my boyfriend was about to watch a soccer game, he took a can of beer from the fridge. I couldn’t help complaining a bit, but had a slip of the tongue. I said, “Why is it necessary to drink football while you watch beer?”