倾国倾城倾你妈倾国倾城倾你爸
[qīng guó qīng chéng qīng nĭ mā qīng guó qīng chéng qīng nĭ bà]
This is a vulgar phrase using traditional flattery terms 'dazzlingly beautiful enough to cause a nation’s downfall' but twists it into offensive slurs involving someone's mother and father. It should be avoided as it’s extremely disrespectful.