How would you describe orientalism? I'm Asian and grew up in the US. I don't really get it, and maybe a lot of discomfort I've felt in my life would make more sense if I could identify when I see it.

Commenting to say that in USia at least, there's a strange connection between orientalism, gender, and anti-blackness. Basically, in the US, asian-ness is inherently feminine, and blackness is inherently masculine.
Look at how this manifests in gendered racism towards the two broad groups:
Asian men are culturally emasculated and considered effeminate and weak (bluntly, they are also assumed to have small dicks), while black men are hyper-masculinized and treated as dangerous savages (who are culturally assumed to have big dicks universally).
Asian women are hyper-feminized (read this mostly as "submissive") and exoticized, treated as uniquely desirable for that "fact", while black women are comparatively masculinized, sometimes derided as "mannish" and unruly and culturally considered uniquely less desireable for that "fact".

It's basically a bunch of bullshit the amcient Greeks thought about others, especially Persia, that has been transmitted with little changes through thousands of years through "western" culture, though who exactly the "west" and what the "orient" is has changed.
The west is full of free individuals, the east are unthinking slaves to despots. Western men are properly masculine, eastern men are either effeminate or have a savage, animal masculinity. Eastern women are titillating and "exotic". Westerners are brave and noble warriors, easterners are a disorganized "horde", if they ever win its just cuz they have superior numbers and no regard for human life. Only the west has real civilization, others are either savages or overly civilized or "decadent" Etc. Etc.
Once you know about it, you see it fucking everywhere, throughout contemporary society and going back literally thousands of years in history, literature, philosophy, etc. It's sickening. The "west" needs to be destroyed, materially, morally, ideologically.
- Like think about the myth of Thermopylae: 300 brave Greeks sacrificed themselves holding off the countless Persian hordes, keeping the Greeks free of the despotic Persian empire.
  (Just ignore the thousands of Greeks that were there who weren't the 300 Spartans, the fact that Sparya wasn't exactly a free society, that Persia was a better society in basically every way, that the reason they didn't conquer the rest of Greece was more that their supply lines were stretched that far away from thier power base, etc)
  We tell ourselves the same sorta myths now
  
  Sparya wasn't exactly a free society
  "Freedom in capitalist society always remains about the same as it was in ancient Greek republics: Freedom for slave owners."
  
  The reason Sparta could only send 300 was because they needed to keep most of their army in Sparta to keep the helots, their slaves, from rebelling.
- A really absurd thing is how the same lazy narratives are deployed across such a giant range of different societies. Like Morroco, Russia, China, Iran, Turkey, Malaysia, and so many other places. All those are basically the same, yeah?

Strong recommendation to read Orientalism by Palestinian American scholar Edward Said, who established Orientalism as a critical concept. It's very approachable, you don't need any other background knowledge.
- Just gonna say that Said is a very enjoyable read. I've read some of his other works (never cracked Orientalism proper, I'm bad), and he is a very good thinker.
  Here he is from "Secular Criticism" pgs 2-3. It gets a bit dense in the back half and he's still an academic, but there's always moments of lucidity like this in the Said I've read (again, can't speak to Orientalism sadly).
  The degree to which the cultural realm and its expertise are institutionally divorced from their real connections with power was wonderfully interested for me by an exchange with an old college friend who worked in the Department of Defense for a period during the Vietnam war. The bombings were in full course then, and I was naively trying to understand the kind of person who could order daily B-52 strikes over a distant Asian country in the name of the American interest in defending freedom and stopping communism. "You know," my friend said, "the Secretary is a complex human being: he doesn't fit the picture you may have formed of the cold-blooded imperialist murderer. The last time I was in his office I noticed Durrell's Alexandria Quartet on his desk." He paused meaningfully, as if to let Durrell's presence on that desk work its awful power alone. The further implication of my friend's story was that no one who read and presumably appreciated a novel could be the cold-blooded butcher one might suppose him to have been. Many years later this whole implausable anecdote (I do not remember my response to the complex conjunction of Durrell with the ordering of bombing in the sixties) strikes me as typical of what actually obtains: humanists and intellectuals accept the idea that you can read classy fiction as well as kill and maim because the cultural world is available for that particular sort of camouflaging, and because cultural types are not supposed to interfere in matters for which the social system has not specified them. What the anecdote illustrates is the approved separation of high-level bureaucrat from the reader of novels of questionable worth and definite status.

How would I describe Orientalism?
The vibes from being a USA'ian were always...
All Asian people are from the exact same culture. There's no difference between the culture, customs, and history of China, Japan, the Philippines, or any other country located on the Asian continent except Russia and the Middle Eastern countries. They all speak the same language and if you meet somebody from, lets say China, they can be automatically assumed to know this other person you know from Vietnam and share their language and customs.
The orient is a mysterious place that is unfathomable. Its the "dark continent" (Africa) but for people likely to be much less dark in skin color.

As I understand it, it comes down to overly simplistic, exaggerated, or just plain inaccurate perceptions and portrayals of people from Africa and South/East Asia. Stuff like
- Speaking of eating dogs, that was apparently legal in the US until the 2018 farm bill

Orientalism is not just a set of stereotypes, but an institution for the production of knowledge. is is the creation, defining, and imagining of "The orient" which conditions knowledge of the orient with domination of the orient. this link between knowledge production and state projects was to authorize a kind of bird's-eye view of the non-Western world, one that positioned the knowing observer as superior in every respect (more rational, logical, scientific, realistic, and objective) to the object of contemplation.
"Said also suggested that there was no simple way out of the orientalist's discourse, that one could not simply substitute "true" representations of the Orient for "false" ones. This is so because representations are more than simply passive reflections of reality. Rather, they contribute to the production of the real. This has especially been the case in a situation where epistemological issues were conjoined with the physical power and resources at the command of imperial states. As the works of those who followed Said have shown, imperial projects constructed an Orient that mimicked orientalist representations, and these constructs were, in turn, recovered by later generations of Western scholars as proof of the timeless regularities of the East"

I've seen in my lifetime school kids my age in elementary school saying asian people have no souls and that they eat cats. Fast forward like 30 something years later, and those kids still have those beliefs into adulthood and are agitating for war with china.
- Honestly the "culturally acceptable" racism towards people from Asia is disgusting. The east/west divide enables people to completely dehumanize them.

read Said, there's also documentaries, interviews, and lectures where he's explained the broad strokes if you're strapped for time. it's a very worthwhile book though.

https://www.youtube.com/watch?v=LR511iAedYU
This is a video specifically about orientalism and Middle Eastern music in films and games. I think seeing how orientalism warps and flattens a specific part of the art we're presented with is a good primer for exploring the concept further.
- One thing I find difficult about orientalism as an aesthetic is that... it kind of slaps, doesn't it (as acknowledged in that video iirc). It's not just music either — so many great villains, settings, costumes etc etc. Like, it's completely understandable and right that you can't do Ming the Merciless anymore, but... that dude had a thing going on
  
  Yeah, its natural for art to develop themes, tropes, styles, and shorthand. But our shorthand for, say, Europe's Middle age doesn't actually replace anyone's understanding of European history. Even if people don't know all that much about it, they'll understand that the art doesn't actually communicate much about that cultural or historical reality.
  Yet as we start drifting outside that peninsula, that ability to distinguish artistic shorthand from real culture starts to drop off alarmingly.
- I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
  yewtu.be
  inv.nadeko.net
  yt.artemislena.eu
  piped.video

OG Orientalism was about the Byzantines and the struggle for self-determination during the greek papacy, when rome was a backwater under east roman control. Especially once east rome adopted iconoclasm to stop the rise of islam, which raised an huge issue, since icons were a beloved tradition of roman culture. Of course romans believed in goldilocks "racism", with the south being nerdy frail femboys and the north being dumb overmanly brutes with big dicks (yes), and the romans being the perfect middle ground.
This caused the fractured between the decadent effeminate emotional greeks vs the temperate stoic masculine latins. This was transferred to the muslims and then east asia. The tropes are basically the same across the times.

Just watch any television show or film from the 70s to the 90s and you'll see the root of it.
The doctors and nerds stereotype is the newer version while the older version is more about spiritualism and magic. Kinda funny how "magic Asian Man" became "Chinese doctor" and "Spiritual and Wise Chinese man" became "Nerdy Chinese man"
There's also the "All One People" trope where cultural identity for all Asian people are flattened. Kinda how all Asian restaurants are labeled as "Chinese restaurants", this is improving thanks to more representation of those subcultures in food and media, but it's still around.
https://tvtropes.org/pmwiki/pmwiki.php/Main/InterchangeableAsianCultures
https://tvtropes.org/pmwiki/pmwiki.php/Main/Orientalism

Orientalism is an idealist ideology. Like every other idealist ideology, it's purpose is to distract from material reality. In this case, it is used to naturalize hegemonic rule over and (desire for) imperialist domination of countries outside the imperial core. An orientalist perspective aims to paint over the real material contradiction between oppressor and oppressed, exploiter and exploited, imperial core and everyone else by instead constructing a dividing line along cultural differences. These are supposedly so impossible to bridge, that the orientalist can only stare at them utterly mystified.
Orientalism is a cultural part of racism. By othering, it also prepares the way for more racist ideology. Racism thrives by creating an empathy gap in white people. Once the gap is established, people who are otherwise perfectly capable of feeling normal human empathy, will just stop caring once it's about the suffering of people they see as the other. Orientalism works like a wedge to widen the empathy gap. By subtle othering it makes people appear as slightly less than human in the eyes of the orientalist and thereby less deserving of empathy. Ironically, since the capacity of feeling empathy is often seen as an important part of being human, one can argue, that it's really the racist who has become slightly less human.
To identify, if a feeling of discomfort you experience might be caused by orientalist attitudes towards Asia, Asian culture and Asian people, you could try to analyze the feeling itself more. Do you feel singled out, like the person (or media, or Institution) sees you as fundamentally different? Do they seem to have a distorted worldview, but also seem difficult to educate? Like, if you don't give them a whole lecture about how things really are, they'll never understand (but who has time for this?) And even if you do, they'll just nod and use everything you say to strengthen their worldview. Like the mere fact, that you have to explain a lot to de-warp their twisted view of other cultures, is seen as evidence for them, that the world really is split because of differences in cultures (instead of the real reason: colonial and imperialist wars).
Reluctance to be educated about orientalist attitudes ultimately stems from the racist holding on to real material privilege, that comes from taking part in structural oppression. That's why orientalist conceptions are hard to get rid of, because they are associated with privileges for white people. Especially in the job and housing market and resulting from extracting wealth from other nations by super-exploitation and unequal exchange. By holding on to orientalism, a white worker can justify:
getting paid more
working under better conditions
living in a nicer neighborhood
receiving a constant stream of cheap goods from countries that are forbidden from establishing labour rights by institutions like the IMF and constantly get the short end of the stick in international trade
belonging to a block of nations, that constantly wages war on the world
Combating orientalism is part of building class consciousness. One approach might be a metaphoricall hit on the nose, where people are made to see the limits of their own freedom in a structured, educational context. These limit experiences (Paolo Freire) can trigger a critical consciousness, where people see how they are shaped by, but also capable of transforming social structures.

seconding the recommendation to read orientalism. I think @toje@hexbear.net overstates how approachable it is (it is after all still a heavily cited academic text), but it's certainly no superimperialism. if you want an example of more modern liberal orientalism, listen to the first 2 minutes of this episode of trueanon which is barely exaggerated satire
- I found a YouTube link in your comment. Here are links to the same video on alternative frontends that protect your privacy:
  yewtu.be
  inv.nadeko.net
  yt.artemislena.eu
  piped.video

The best way I would describe it is overemphasizing that it’s foreign, and usually part of some sinister plot. There is a large amount of overlap between antisemitic stereotypes and anti-Asian sentiment (particularly anti-Chinese) sentiment, for example.
Sometimes when anime or pokemon was spoofed in the aughts, the animators would get kind of…weird about it. Even some parents and school faculty members would see it as a bad influence, and anime had a moral panic against it. Hell, Pokemon risked having the iconic pokemon redesigned just for the US.

The ocean? what ocean?