Theoretically, it is possible to draw both positive and negative energies through a person when they undergo a treatment. For practitioners who are exposed to the negative energies of their patients, this can lead to unwanted outcomes and may even affect their ability to heal. Consequently, most practitioners will attune themselves to the universe so that they are operating harmoniously with it before beginning a treatment session. Once someone is properly attuned, potentially negative outcomes are minimised. Very often, a single attunement is needed, but a so-called shower can be used to protect all those involved in a session so that negative energies are washed away, metaphorically speaking, prior to opening up channels of universal life force. Some would argue that practising before being properly attuned could do more harm than good, so it is a necessary part of the entire belief system surrounding the practice.