You don't have to rub it in. I already feel bad enough as it is.
不要再火上浇油了，我已经够难过了。
rub it in直译过来就是：“反复摩擦它的里面”，这个短语的正确意思是：“火上浇油，故意触人痛处”。因此，当美国人说"You don't have to rub it in. I already feel bad enough as it is."时，他/她要表达的意思就是:"Don't pile on. I've felt bad enough."、"You make it worse, and I am upset enough."。
情景对白：
Benjamin: I know the boss blame you again. If I were you, I would teach him a lesson.
本杰明：我知道老板又批评你了，如果我是你，我一定给他点颜色看看。
Shirley: You don't have to rub it in. I already feel bad enough as it is.
雪莉：不要火上浇油了，我已经够难过的了。
搭配句积累：
①I didn't expect that you would laugh at me!
我没想到你竟然会笑话我。
②Don't bother me and just leave me alone.
别来烦我，让我一个人待会。
③Please get away from me if you come to see my jokes.
如果你是来看我笑话的话，请你离我远点。
④Will you keep your mouth shut?
你就不能闭嘴吗？
单词：
1. rub vt. 擦，摩擦
He rubbed and rubbed but couldn't seem to get clean.
他擦了又擦，可就是擦不干净。
When object rub against each other, static electricity is produced.
当物体互相摩擦时，静电就会产生。
Gently rub into the skin until absorbed.
轻轻揉搓，直到吸收到皮肤。
2. pile on 堆积……之上
She will pile on the agony when she desctibes her visits to the dentist.
她描写就医牙科的经验时，把痛苦说得言过其实。
Pile on more coal; the fire is going out.
火快熄灭了；再加上一些煤吧。
