I spent 2.5 months living in Puerto Alegre and Estiron, 2 Matses villages. The Matses are a remote Amazonian tribe who live on the border of Peru and Brazil in the Javari Valley.
One of the Matses villages was very welcoming and is more than happy for other adventurers to come and stay.
If anyone is interested please contact me at paddy.leflufy@gmail.com