笑得没心没肺口哭得撕心裂肺口
[xiào dé méi xīn méi fèi kŏu kū dé sī xīn liè fèi kŏu]
The name literally means laughing heartlessly but crying bitterly. It depicts the emotional extremity that this person can both express joy and sadness without reservation, conveying strong yet opposite expressions as their two different aspects.