Actual translation could be: “Nahulog ito sa maling tubo”. It would be referring though to pipes or tubes made of metal, plastic, etc. If it’s about the throat, what we’d speak of in Tagalog is not the anatomical cause, i.e., that something went down the wrong pipe, but its consequence. I guess that’s because the cause or reason is almost always a given. There are 3 common terms that we use – “samid” (infinitive is “masamid”), “hirin” (infinitive is “mahirinan”), and “bilaok” (infinitive is “mabilaokan”). These refer to the coughing reflex or a kind of asphyxiation that happens. “Masamid” is normally used when the cause is a very small item or a throat irritant, e.g., a grain of salt, dust, pepper, cigarette smoke, etc. “Mahirinan” is also for small objects, but usually, food stuff. “Mabilaukan” is for bigger items that may even cause choking. Thus, we’d say “it went down the wrong pipe” instead as “nasamid/nahirinan/nabilaokan ako”. So, if we end up with the coughing reflex and were asked, “Anong nangyari?” (What happened?), we would reply with something like, “Dahil sa kanin” (Because of the rice). That is, we would not explain how it happened, but rather what it was that went down the wrong pipe.

Not really an answer but a clarification. Most likely, William's asking about the American idiom rather than an object going into a literal pipe. You would use it to refer to what happens when you drink something and some of it goes into your windpipe, causing you to choke and cough. If that's the case, I don't know how to translate this phrase but I hope I've helped out someone who can.

Hi so if you literally translate the "it went down the wrong pipe" part, it would be "bumaba ito sa maling tubo/alulod" I think the colloquial way to say it would be "lumusot yung (meantion whatever item it was) sa maling tubo/alulod" I put tubo/alulod because usually, a word like pipe I just say it in English and so it becomes a taglish sentence, but since you want to say it in Tagalog, there are actually two words for pipe. There is tubo and alulod. For tubo, it actually has a lot of different meanings depending on the translation so if you can find someone to distinguish those, it would make more sense, but I suggest you stick to alulod or make it taglish and say pipe.

It went down the wrong pipe. -Ito ay nahulog sa maling tubo.