In the mouth of the wolf

For one reason or another I was talking to a friend about phrases. Not English ones but ones we liked it other languages and wished were in English although I do wonder what a native speaker would think of our word choice or maybe they don’t care. One of them is in french bon courage, which just means go with courage and I like that. In English we just say good luck or maybe break a leg. But nothing like that has much more power. The same phrase in Italian is a bit more intense is in bocca al lupo, which means instead of good luck or go with courage it means in the mouth of the wolf. This you are supposed to reply crepi, so that he dies. The wolf whose mouth you are in. I don’t really know any phrases that compare to this in English. But I wish we had one. Italians also use it because they are concerned about wishing good luck, superstitious, they think it will bring bad luck. 
So instead of the normal buona fortuna or good fortune, they wanted to get a wolf involved and your in its mouth and you want it to die and this is somehow safer and more normal than saying good fortune. 

I like it and I think we need our own.