I know that "in bocca al lupo" means "good luck", but what's its origin and when is it used?
Let me copy down the (not completely satisfying) relevant entry from Carlo Lapucci, Dizionario dei modi di dire della lingua italiana (Garzanti-Vallardi, 1979):
Oggi [«In bocca al lupo!»] è un augurio che vale: buona caccia! Per i cacciatori tuttavia le due frasi non sono ugualmente gradite, e preferiscono di gran lunga la prima, mentre considerano un grande malaugurio la seconda, di per sé innocentissima. I profani devono fare attenzione. [...] [The phrase refers to] trovarsi faccia a faccia con il loro naturale avversario che è la selvaggina: situazione da cui essi sapranno togliersi uccidendola.
Infatti all'augurio: In bocca al lupo!, il cacciatore compìto risponde: Crepi! (Il lupo è sottinteso).
So, in a sense, you are apparently wishing for a dangerous situation, but implicitly suggesting that your friend will be successful.
I myself do not know any hunter, but «In bocca al lupo!» is used quite frequently before exams, performances, job interviews and the like, while some people (like the hunters of the above quotation) would consider a more straightforward wish to be unlucky.
Compare the above with the English “Break a leg!”
I think it goes back to the founding of Rome fables. Romululus and Remus, orphans raised ferally by a she wolf as her own pups. "Go in the mouth of your wolf mother. She will protect you". The idiom has evolved over a few millennia to mean, simply, good luck. I think the "negative" connotations, meant tongue in cheek, developed from the inevitable misinterpretations of oral histories.
I am new to this delightful exchange, so please accept my groping attempts to communicate.
My only source is a couple from outside Verona. They visited my family in the u.s. around 1981. Wonderful people, Angelo and Adela. They own a vineyard and winery there. Her family was from the environs of Roma for a very long time, centuries.
I have no other citations nor references. It just seems right to me. Logical and plausible. The lack of literary sources and the gender issue of "lupo/lupa" are perfectly valid. I just don't know.
But without any hard evidence of origin, the nurturing, protective version is preferable to me over the snarling, ravenous, near escape from a gruesome death scenario.
Purely an emotional response I'm sure.
I hope someone with more resources and better Italian can find something more, but in the meantime I'll cling to my kinder, sweeter version.
And besides, it still means what it means.
Boca lupo(a) mi amici...
No no no no no!!!! All answers are TOTALLY wrong!! Let me explain why! The female of the wolf, when it has her puppies (her 'children'), it use to put them in her mouth to PROTECT them from external attacks.
So, when somebody says "in bocca al lupo" it means "I hope you'll receive a protection". So the correct reply is "grazie", that means "thank you (that you want to 'protect' me)! Do you understand?
I'm Italian, but also some Italians don't know the correct origin of this phrase! Now you know it!
When we were visiting Rome and during a tour of the Roman Forum conducted by a university professor, he told us that the expression "in Bocca al Lupa" or in the mouth of the wolf originated from the founding of Rome. Romulus and Remus were suckled and protected by the she-wolf who took her pups in her mouth for protection. Thus the expression meant, may you be protected or be safe.