I have done them a small handful of times. Once walking around downtown doing them with a guy I knew who was sort of a bad friend and immature person. At first I was comfortable with the trip and was feeling joy and mind expansion and a connecdtion to nature. Then he tried freaking me out by saying hey look at the ground its waving and I convinced myself I was seeing the same thing as him because I was high and stupid and it all became overwhelming. I realize now when I started doing drugs was bad people I had calling them friends, and I think that is the case with most people who do drugs and I hope that's not the situation your in or even considering taking them.
I had reached blissful states in meditation for the first time prior from my trip and I can tell 1. They were much better than the drugs. 2. I regret the drugs because they are destructive to your meditation practice.
The other times I did them was hell, one in particular where I did 50 dollars worth at work then another 20 after and got lost in a parking lot. I was talking to brooms instead of washing dishes.
Don't do them with people you don't feel 100% comfortable with, if you're stressed and have to do something the next day, are afraid, are going to be in a highly stimulating environment, and don't have access to nature.