A dolgok nagyon csehül állnak. Nagyon csehül vagyok, fáj a fejem és lázas is vagyok. 'Things are going very badly. I feel terrible, have a headache and a fever, as well'. We're not dealing with the most pleasurable feelings, here.
The term csehül probably dates back to the 15th century, when Upper Hungary was ravaged by Czech soldiers. The revered Hungarian poet, Sándor Petőfi, connects it to Vladislaus II aka László Dobzse, a Czech king, successor to the legendary Mátyás. Unlike Good King Mátyás, László Dobzse, his name a Magyarised version of Czech for 'Fine, whatever', brought decline to Hungary’s previously well-off kingdom because he was so indecisive and let the noblemen get away with anything.
But, interestingly enough, the Czechs also use their
equivalent of ‘Hungarian’ in a pejorative sense, meaning 'to speak
meaninglessly'. The riposte to this from the Hungarian side is probably the verb csehel, which used to mean the exact same thing: to talk nonsense.
Nowadays, it’s
not used any more in Hungarian but its leftovers can be found in the verb csahol which refers to how dogs yap.
Switching back to history, there was an important battle in Hungarian history, which probably contributed to the introduction of csehül áll into the vernacular. In 1278, the Hungarian king brutally destroyed the army of the then-wealthy Czech king, Ottokar II, but also died in the process.
And this may be when the saying, csehül állunk, somehow stuck – when Hungarians were actually stuck and suffering the same fate as the Czechs. An authentic example of Czech, mate, as it were.