Depends on the drugs, the set, the setting, your mindset.
You can smoke the right sort of weed and go on a journey of realisations and epiphanies, actively rewiring your brain into a state of openness, causing a fuckton of new connections to be formed and old ones to be strengthened, ending up in causing a massive boost in creativity.
Or you just sit on the couch, bathing in the feeling inside of you.
A little bit of cocaine and you're just awake and aware, a little bit too much cocaine and your ego explodes, exposing a lust for sex and power.
A lot of the experience also depends on your ability to introspect. The better your connection to your body, the better not just the experience, but the easier you can drag it into normalcy.
I could go on and on and on, I guess.
One thing's for sure, though: There's no reason not to explore different states of mind.
There are many types of high, so it's difficult to explain. It's extremely personal in a way that you want to share with everyone as it likely is one of the best times of your life sitting there and feeling the ecstasy and glory of everything around you, but I'm not confident there's a language that can express the feelings of joy and pleasure in a way other than to spark curiosity in a listener. I can certainly try though to describe some more positive experiences.
All wayward thoughts, the problems that bog you down, the sad thoughts and feelings that creep in or the little worries about what you need to do today, tomorrow, next week, they don't appear as tasks or problems, if they appear at all. If they do, there is an unbridled energy towards how well you're going to handle them, and then they're out of your mind. As you approach the peak of your state, there is a rush to your head like a warmth, a little unnerving at first, but it will just let loose over you and you'll feel your body let go of stresses and tension you never realized you had.
Uncontrollably, you'll start to smile and want to share what you're feeling with anyone around, finding the joy of life in absolutely everything. Everything will seem more real, with small details that mesmerize you and astound you and you focus on with incredible attention and admiration. Imagine the scenes you've probably seen in movies or TV shows where someone is stunned by the beauty of a piece of art or by music, and then try to imagine how powerful the emotions would have to be to stop you in your tracks and just gaze upon something that registers to you as pure beauty. I once stared at puffy white clouds against a huge blue sky, and they had a silver shimmer outlining them, each cloud seeming "happy" to just be a cloud floating in the sky, sharing their happiness with the world below them. As I took in their happiness, I felt I "gave it back" and they loved and appreciated our connection so much, they shimmered even greater. The vastness of how far the clouds stretched and reached felt immense as logically I could know they stretched for kilometers, but at the same time it felt as if we were in the same room sharing our positiveness with one another. (To this day I cannot look at clouds without smiling, even when completely sober)
Tastes and feelings are taken to something else, as even sipping on a simple glass of juice felt like drinking from the divine, whatever that means, and every molecule of the juice was friendly and soothing to every part of me it touched, and gladly gave me its energy to help me feel stronger and better, and I thanked every drop as it rejuvenated me because I felt so close to each and every moment and was almost brought to tears as I thought of how much work had to happen for this fruit to become a juice, the care and love to grow the plants and to bring them to fruition and now the juice shared the same love and care it had with me as it gave me energy and refreshed me.
If you're with people, you want nothing but the best for them and to tell them how much they matter and how wonderful they are. You never lie, but you also find the positive in everything and even if sad subjects do come up, you cannot help but approach it from a strategy of understanding, and conflicts are anything but that, you just want to show that no matter what they are loved and appreciated and that they matter. Even telling of such subjects isn't an offense, it's a brave and human act of someone who wants to grow, and you want to help them grow, so you even thank them for the offenses and want to help them take the next steps they want to become the best "them" they can be.
During this time, your entire body relaxes in ways maybe you've felt before. If you've ever had a partner and held them at night and realized you didn't know when your body ended and theirs began, it's a similar experience, but when you're on a high, it's an intensity of comfort and happiness that really cannot be described. For hours, you barely feel the weight of your own body while having full control over it.
For other highs, everything just seems more "intense", both the good and sometimes the bad (hence, bad trips). You will think and understand yourself in ways you consciously avoid, and it can go either way depending on the conditions you prepare for. Directing your attention to the simple things like calming music, some gentle twinkling lights, it brings you to the same joy where you just can't compare it to any sober experience as everything is enhanced. There is a beauty and "feel" that inhabits the world as you see it and all things have a significance you cannot ignore.
It's incredibly broad. I'm not trying to quibble, but it depends on what you mean by "high". There are two major overlapping groups of experiences you could be talking about. There's the euphoria and energizing high associated with stimulants (see Jones, Casey 1970). Then there's the psychedelic high. The second one is what's being talked about here. (Again, these experiences aren't distinct but it would more clear if they each had their own word).
The experience of a psychedelic high is incredibly broad. It's like asking "what's it like to experience a vacation?". It might be relaxing if you're on the beach in Barbados. It might be exhilarating if you're skiing in the Alps. It might be serious work if you're cave diving in Tulum. Then there's the individual experience. Do you feel relaxed and free from your job? Do you feel stressed because you can't stop thinking about it? Fighting with your family? Connecting with them? Lonely? Content?
In defense of the person you're replying to, someone could give you an impression they've never been on a vacation by the way they talk about it. It's not that their experience is different than yours, it's just that what they're saying doesn't seemed to be informed by any sort of experience at all.
Even though psychedelic highs are incredibly broad, there are a few common (usually opposing) themes. The first is hallucinations. These are perceptions that aren't real, or more generously, outside of consensus reality. If the paint on the wall looks like it's flowing, it won't to anyone else in the same room. At least not in the same way. You could feel a snake wrapping around you, but a video recording wouldn't show one. Then there are delusions, which are beliefs disconnected from reality. You believe you're Jesus. You believe someone is out to get you. You believe nothing bad could possibly happen to you.
You could feel complete boundary dissolution. Everything is one. Or, strong separateness. You're talking to the parts of yourself as distinct, external parts. Or are communicating with a spirit. Faded memories can come back, or you can have trouble remembering anything. Fearlessness or fear, heart rate increase or decrease, peace or terror.
Decreased motor control is the only thing I can think of close to universal, but it isn't. There are reports of people having temporary increases in motor function, often in an area that is deficient due to physical trauma.
Anyone who answers your question with a few simple declarations is like answering "what's it like experiencing a vacation?" with "You take a break from your job, go somewhere sunny with your family, have a nice time doing fun and relaxing things, then feel refreshed when you go back to work". It's not even an oversimplification. It's a sample presented as a summary. Suitable for a telling a 3-year-old what "vacation" means, but certainly not right.
I've definitely had experienced polar opposites that both involved visual hallucinations or delusions / shifts in belief.
For example, I've experienced the belief that my life is a beautiful story where everything is going to be revealed to be part of some sort of divine plan, with people in my life turning out to have some kind of angelic knowledge and agency in this plan.
I've also experienced the belief that existence is a horrendous joke, and that everything from physical reality to my identity is actually some kind of swirling prison-prism that is eternally flowing into horrible nothingness.
Well, those are both true in certain ways and false in other ways. But boy were they experiences.
