In these negotiations I'll play the bad cop and you play the good cop.
Tips
culture
Opera face colours mark character: 红脸 loyal and brave, like 关羽; 黑脸 upright and fierce, like 包拯; 白脸 crafty and treacherous, like 曹操. From this comes 唱白脸, "to sing the white face": to play the bad cop, the opposite of 唱红脸.
mistakes
Not the same as 小白脸, a pretty boy or a man kept by a woman.