Did they actually have vomitoriums (vomitoria?) in their homes or was my Latin teacher just taking the piss?
In their homes, Cameron, No. That would be bizarre. But in their amphitheatres, absolutely yes! Here is a picture of one:
Now, being the big old smartypants that I am, I have a strong suspicion that this is a highly disappointing picture. This is clearly a passage, and not a place where people would gather to puke for fun. Especially not the Romans, who as we know preferred to do things indoors surrounded by pictures of dicks. Note the lack of dicks in this picture.
I'm sorry dear readers, but a vomitorium is not a place where Romans went to throw up during meals so that they could eat more. It's a passageway into/out of an amphitheatre so named because people spew out of it (broadly). It basically means EXIT. On top of that terrible news, the term only appears in the Late Fourth Century in Macrobius and hardly anyone has read Macrobius even though he's quite interesting. Cicero wouldn't have even heard of such a thing. The idea of the puking room was made up in 1961, around the time that everyone stopped thinking that the Romans were great civilizing force for good (because the Nazis ruined imperialism for everyone) and started thinking that they were just a bag of vile, gay, evil weirdos.
So why does everyone now think that Romans are decadent monsters? What happened to the civilizing geniuses in white togas idea? The answer is threefold. Because nothing is ever simple in history.
1. Morality Tales
The Romans were a didactic, pompous lot. They were almost the best ever at being incredibly judgy and gossipy about each other all the time. Even better, they were a rich and literate society where most of the gossips were rich in both money, time and motivation to write down all their moralising stories about each other and then publish them widely. One of the best sources for terrible tales of debauchery told to horrify and titilate a Roman audience is Suetonius's Twelve Caesars, a set of biographies of the first twelve Caesars of Rome - from our friend JC to Domitian - told in thematic rather than chronological order. Just about every crazy, hilarious thing you've ever heard about an emperor came from Suetonius or a misunderstanding of Suetonius. Caligula made his horse a consuls? Misunderstanding of Suetonius. Tiberius and his sex grotto? Suetonius. Julius Caesar and the pirates? Suetonius. Nero fucking his mum? Suetonius. Caligula fucking his sister? Suetonius. All of it from one guy. Whose other best seller was called Lives of Famous Whore (now sadly lost).
Here's the problem: Suetonius had no desire to actually tell the truth about anything and is widely known among students as the Heat magazine of the Roman world. The whole point of Roman biography isn't to tell the capital T Truth - that positivist, scientific, very modern, imaginary thing - about anyone, but to give the reader an impression of the general idea of a person. And if that means that sometimes a few incidents get invented, or inflated, or obvious gossip gets reported then that's not a problem. By reporting senatorial gossip and rumour, Suetonius is saying "everyone hated him so much that they said stuff like this about him." Everyone thought Tiberius was such a tosspot that they said he was a pederast. Everyone though Caligula was such a twat, they said he fucked his sister. What they're NOT saying is sisterfucking, pederasty and giant golden statues of yourself are totally cool behaviour in Rome. They're saying the exact opposite: we hate this guy so let's say the worst thing we can think of about him, accuse him the most unacceptable, anti-Roman behaviour.
And this is all fine as long as your work is only being read by Romans who get this context, who understand that the point of the story about Nero and his mum is to make one gasp and mutter about good Roman values.
Sadly, it isn't and these survived while perhaps more sober histories did not. And they survived for the second reason.
2. The Christians.
The early Christian, for reasons mainly centering on the fact that the Romans kept trying to kill them, were not fans of the Romans. And early Christian theology is very, very heavily focused on ideas of suffering, renunciation and asceticism and does not look kindly on things like giant global empires full of rich people who do art, spend 8 hours a day on their hair and own 5 houses. Early Christian theology, if you remember your gospels, are enormous fans of giving up all your possessions and cash as well as sex, food and fun in order to prepare appropriately for the second coming of Christ (happening any minute in the first 250 years of Christianity). Therefore, anything they can get their hands on that suggests that the pagan Romans likes things other than mortal suffering were pretty good for demonstrating how evil (in the Christian sense) the Romans were and how great Christianity was in comparison. Especially if they talk about sex.
Then the Christians win, surprising even themselves, and they have to come up with a reason why imperial Roman power in the West collapsed so easily in the face of (to the Romans) 9 pathetic men in furry trousers who couldn't read Greek. Their answer of course was that the pagan Western Romans were a bunch of filthy, depraved, over-paid, under-worked sex maniacs who were punished by God for all this with the loss of the empire. Western Christian writers of this period were particularly fond of pointing out the unshakable and imaginary moral goodness of the Vandals in comparison. And look! There's all this evidence that the Romans were gross in books like Suetonius! Urgh, Romans. Yay Christians.
And so, throughout the middle ages, because it's relatively poor and there are no lazy aristocratic classes to do art, literature exists only in the church and only ancient texts that support Church ideas tend to survive. Like Suetonius, who proved that the Romans were awful. And so it goes for a millennium or so, until the Renaissance happens (by magic I assume), Europe rises from the ashes via some process or another and start banging around all over the world oppressing and genociding everyone they come across and starting wars with each other. Which brings us to the last reason.
3. The Twentieth Century
WW2 has two major effects on the Romans: first the Nazis explicit association of themselves as the inheritors of Rome, adoption of the Roman salute and desire to build a new Roman empire squicks everyone out about the Romans; second the aftermath inadvertently kickstarts the cultural and sexual revolutions of the 1960s onwards. This means that no one wants to be nice about Romans, and new sexual morals mean that all the filthy stuff can finally be translated. On top of the the Americans start getting really pushy and meddle-y about global affairs while having a senate and an eagle and all kinds of Roman paraphernalia in their iconography. That makes everyone start talking about New Romes again, in a bad way. Rome is once more associated with richness and decadence and immorality and imperialism.
Plus, the western world is still crazy rich and being crazy rich makes everyone feel bad. This means that we can all look back to the moralising tales of decadence of the Roman empire which have conveniently survived and see ourselves in them. "Ohh" we can sigh, while watching My Super Sweet Sixteen in our big centrally heated houses "it's like the last days of Rome" and we can all feel better about ourselves. Which - conveniently - is exactly what the Romans wrote all this stuff down for in the first place. Because everybody thinks they're a Suetonius, and no one wants to be a Nero. Except those kids on My Super Sweet Sixteen, who are awful.
In this climate, the idea that the Romans were as godawful as we think other people in our own society are (Germans, Americans, teenagers, not us) is terribly attractive and its just a little step from there to start openly making stuff up about how awful they were, like vomitoria. Just watch Caligula for further examples.
So there. Why do we think the Romans had vomitoria? Because they were moralising gossips, because the Christians thought they were bastards and because the events of the twentieth/twenty-first centuries have fertilised the ground for hating them. Easy. Now none of this should convince you that some Romans weren't astonishly decadent, big haired horror shows with too much money and not enough taste, merely that the Roman world was not the grab bag of normalised, horrifying, physical and sexual degradation that vomitoria suggests. They were much weirder than that.