I am diabetic and should test the sugar content in my blood at least once a day, actually after every meal, but the little white plastic sticks cost enough (although the insurance pays 90%) and so I avoid it generally.
However, the German expression for the blood sugar level is “Blutzuckerspiegel” literally translated, verbatim, “blood sugar mirror”. So if you blood sugar mirror is down, then you have a low level of sugar in the blood.
You can have “pig” in German, meaning luck. Where the “dog is buried” is the solution to a problem. If she has a “bird”, she is not quite in her right mind, which is also explained by not having “all your cups in the cupboard” and if you only understand the “railway station” it means you do not understand anything. You can also be the “insulted sausage” meaning you are annoyed.
And this goes on. Yes German can be quite confusing. I will not even begin with the Swiss variations.