I think it is important to do it in the right mindset and with the right intentions. Most people associate MDMA with partying, and while that may be one use, I don't think it is necessarily the best. I don't even understand how people go party on mushrooms. I think the best is to be somewhere safe and quiet, outdoors hopefully on a sunny day with someone you trust or by yourself and just to sit and think and write if you can.
A certain amount of training beforehand doesn't hurt either. I'd been meditating for quite a while, and I'm no expert but I had a level of trust about what I could handle in terms of experience.
After the first couple of hours of my trip I introduced a lot of metal music and horror films to see exactly where it would go. There was nothing pleasant about that experience but I felt together enough to still observe it without being lost in it. However I couldn't consider deeply enough how horrifying it would be if you didn't have some sort of anchor inside of the experience.
It is a matter of looking at these substances as entheogens (http://en.wikipedia.org/wiki/Entheogens) and not a party tools and considering yourself a Psychonaut (http://en.wikipedia.org/wiki/Psychonaut) and not a party animal.