touch-and-go（Used to say that the result of a situation is uncertain and there is a possibility that sth. bad or unpleasant will happen.）:

触摸和走 ×

情况危险的 ✅

例句：

She’s fine now, but it was touch- and-go for a while.

她现在好了，但是她曾经一度病危。

be / live in each other's pocket :

在对方的口袋里 ×

形影不离 ✅

例句：

They are in each other's pocket.

他们形影不离的。

dead meat：

腐败的肉类、倒大霉 

例句：

If anyone finds out, you are dead meat.

如果有人发现，你就倒大霉了。