"Among the forest-dwelling Kichwa people of the upper Napo [Amazon], the Guayusa brew is known as 'Waísa' or 'Waísamama', a word that conveys the concept of a certain kind of power or energy found in nature–that of medium-sized rivers that run crystal clear. This same subtle energy can be cultivated and accumulated over time in a human body, and the results make one strong, happy, and wise. In order to accumulate this subtle and sacred power or energy of the river, guayusa tea is consumed every day, very early in the morning, at the wee hours of predawn. 

Then one bathes in the river shortly after, before the first bird sings, most specifically before the hummingbird bathes. Waísamama is waísa combined with 'mama', meaning 'mother, power, authority, or protector.' To drink waísamama and gain the river's waísa is the Kichwa health-insurance policy, as one who embodies the waísa will not easily become ill; on the contrary, this person enjoys good health, laughter, and vitality.

Once the hummingbird bathes, it is believed in the science of the people that it takes the river's waísa away for that day. After the stillness of the night it is restored while the hummingbird sleeps. This is why if one can bathe before the hummingbird, then the river's energy is available to be absorbed into one's being at that time of morning. The hummingbird is representative of perfection: its feathers always gleaming, its energy vibrations high. It is believed to be like this because it gathers the waísa from the river."

From the book "Rainforest Medicine" by Jonathon Miller-Weinberger