When I introduced one of my friends to it, I looked him dead in the eye and said, "There's a chance you will feel a body wide orgasm for 100 years, there's a chance you'll get raped by 30 demons, and there's a chance that nothing will happen at all." He was alright with this and we went ahead.
Of course that friend was already somewhat of a psychonaut, so I think he was very ready. That specific night didn't turn out to be that great, but on some subsequent nights it got a lot better. The key is to let go and be willing to go anywhere. Let go of fear and of your ego. Stop thinking and let the magic take its course. It's kind of like a roller coaster ride, if you want to use an analogy. Once you're buckled in and the ride is going, there's no turning back. Might as well enjoy the experience, right?
It would be good if you tried the 15 mg as you say so you can get a handle on how powerful it will be. This is a great strategy, and then your friend can decide whether or not to pursue it.
"Think for yourself and question authority." - Leary
"To step out of ideology - it hurts. It's a painful experience. You must force yourself to do it." - Žižek