no kuchi ni naru
have a mouth (for certain food)
to feel emotionally ready to eat something and don’t feel like the other foods at the moment
For instance, you may have “a mouth for ramen” after watching a TV show that features famous ramen restaurants.
What? The yakiniku restaurant you were just talking about is not open today? Coz I’ve got ready to eat yakiniku already, let’s find another yakiniku restaurant!