Ayahuasca ceremonies are usually very structured rituals where the shaman or shamana holds the space and guides the drinkers on their journeys of discovery. The shaman is not just administering the hallucinogenic brew; he or she is also calling in their allies, banishing evil spirits, and safeguarding their immediate physical environment–playing the role of psychic bouncer. And while personalities vary, the role of the shaman in anchoring the physical and spiritual worlds is inviolate, and should be treated with respect.