A way to search for alternate idioms?

I'm having real trouble with having the perfect thing to say be a figure of speech, but it's outside of the culture of the speaker. Does anyone know a good website I can use to find alternate idioms based on meaning? Or at least a good site for the roots of certain expressions?

Earlier in the fic, I had to translate "You are out of your depth" into "You are leaping from the heights in your fuzz" because I didn't think swimming metaphors are something that come naturally to an avian.


The one I'm trying now is "He was pushing your buttons" but it's not appropriate for someone who grew up in the dark ages, besides sounding undignified.

How about coming up with your own, as you already kinda did with that translated-to-other-culture example? It gives extra flavour to the world.

For even more worldbuilding nerdiness, make up a setting-appropriate origin for the figure of speech, such as a historical event or national stereotypes about the local nonhumans.