I have done 3 ceremonies, and can definitely say that it is beyond life changing.
You need to ensure you are doing it with experienced shamans who take the time to get to know you beforehand so they know how deep to bring you. It is also very important that there sufficient shamans and assistants for the number of participants. The assistants don't partake themselves, but circulate to ensure that nobody runs off into the woods or chokes on their vomit etc.
I have done all of mine in Canada, with shamans who are from Peru. There have always been at least 4 shamans and 8 assistants, with the largest number of partakers being 17.
Taking certain medications within a few weeks of Aya can kill you.
You will also have a much more in depth experience if you heed the nutritional guidelines for at least 2-4 weeks prior to your journey, and not just during it.
There are a number of reputable groups in Canada who practice this regularly. However, it is not legal here, so it is quite underground, and usually by referral of a current participant.
Yes, you can extract DMT yourself, but the experience is absolutely nothing like doing it at a proper ceremony. Icaros influences things beyond words. And taking DMT in a smoked or injected manner only lasts a few minutes compared with many hours at ceremony.
If you follow the preparation, have sufficient supervision, and know that the shamans in charge are experienced doing it for the right reasons - healing and neural Theology, then you should be perfectly safe and have a life altering experience.
I'm still processing my last one - and it has been 3.5 years. I asked to go as deep as I possibly could without causing my physical body to die - and I had my ass handed to me!
