This fits nicely into my series of helpful posts about things you can put into or on your ears (pins, candles, your little finger) but is in fact the title of a book I have just acquired. To a Russian the expression means I'm not pulling your leg.
Other idioms from around the world which are featured in the book are When dogs were tied with sausages (= very long ago, in Uruguayan Spanish), To distribute cardamoms (= to invite to a marriage, in Hindi) and To walk around hot porridge (= to beat about the bush, in German).
The book is amusing in a quiet way but not really of much practical use: it would be foolish to learn any of the quainter idioms in the hope of impressing a native speaker of the language, because the chances are that you would misuse them or that they are desperately old-fashioned or hackneyed expressions which would give away the fact that your knowledge comes from a book and that you don't actually speak the language at all; either way you would look silly.
The compiler cheats a bit by including a few proverbs; the English translation of some of these would make good conversation-stoppers, particularly as they are mostly incomprehensible. Come out with "Don't look for yesterday's fish in the house of the otter" and you are bound to get a mystified silence, unless there is a Hindi-speaker present who will recognise it.
So you could invent your own idioms which no-one could challenge. Having checked that there are no Albanians listening, you might say of someone you are discussing: I bet his elbows smell of horseradish and then explain that in Tirana this means that he is a man not to be trusted.