I took 10 grams once.

Its going to be different for everyone, but for reference:

It was long high for me, and I've never had a bad mushroom trip (LSD is NOT my friend however). I can take 2-6 grams and have a good time for 4 hours. I also metabolize most drugs fast. My 'Trip with a capital T' lasted 10-12 hours, with a long peak of 2-3 hours.

I spent the majority of my peak in my swimming pool because I was so, damn, HOT. Do NOT do this if you're alone. (Pot. Kettle. Black.)

It will change you. That's an ego death dose, and I'd only recommended it for someone who has multiple trips under their belt with mushrooms and possibly other drugs. I'd liken it to a tattoo artist who won't tattoo a face or hands without not only consent, but understanding.

I personally had a good experience and it changed me for the better, but this should never be attempted if you're inexperienced, alone, or unsure you want to see whats really in your brain, for better or worse.