This chapter explores participatory methods for the Symbiocene, an era of harmony between humans, non-humans and material entities. Building on the limitations of the Anthropocene, it argues for transdisciplinary approaches that combine new materialism, allyship and multisensory methods to address global problems like HIV, climate justice and systemic inequalities. An argument is made for advanced participatory methods to speed up the journey to the Symbiocene. A research study with young women living with perinatal HIV in South Africa is used to show how adherence to antiretroviral therapy is influenced by entangled interactions between social, environmental, material and systemic factors. The Assemblage model is introduced and shows both human and non-human entities’ relational intra-actions and the agency to produce phenomena. By using multisensory methods, the research shows how environmental triggers and material realities shape health behaviours and offers new ways of fostering adherence and well-being. The study shows the power of allyship in participatory research, moving beyond symbolic inclusion to co-create equitable and impactful theories and interventions that can redefine human and planetary health.