你长发及腰我便咔嚓一刀
[nĭ zhăng fā jí yāo wŏ biàn kă cā yī dāo]
The phrase 'Once your hair grows long enough to reach your waist, I'll snip it' might imply the speaker wants to make a change in his or her relationship with the subject of affection or express dissatisfaction through metaphor.