Half of these exercises have NOTHING to do with getting high (Parkour? Sitting near a waterfall?). Other exercises stretch the limits of what getting "high" even means (yes, you'll see colors if you rub your eyes, but is that really the same thing?).
However, some of the other exercises probably work. I haven't tried them yet. Either way, this book is unique, funny, and gives you something fun to do in your spare time. I recommend it.