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

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. This page is great if you'd like more examples, and examples are the best you're going to get: https://psychonautwiki.org/wiki/Subjective_effect_index https://psychonautwiki.org/wiki/Subjective_effect_index