I agree on hydration, but for what i have read in these years on kambò, this idea to drink water is not in the natives' tradition. The reports I read speak they eat a soup or broth of manioca, preferibly.
Manioca (also known as cassava, tapioca, mandioca, yucca) is a palatable white tuber rich mostly in carbohydrates.
Someone has more precise infos on the traditional recommendations ?
However I think that vegetal juices are more suitable to hydrate than water, at least if this water is NOT very pure and light, without minerals in solution, because these minerals are in the inorganic form and they tend to obstruct and engage the body in a further process of elimination. The organic water of fruits and raw herbs is instead rich of minerals in ionic form, easy to absorb by kidneys and mucoses, contributing to a good electrolytic balance and support to neurons and organs.
To drink too much water in a short time is not very safe as commonly thought.
I feel one liter in my belly is enough to be tolerable, more creates discomfort.
And in every case i suggest it's better to drink water in small sips.