The idea that research on infants should "voice" their "perspectives", their experiences, what they are "really saying," is a central feature of current moves toward participatory research. While embracing the ethos of participation, this article steps away from the binary logic of identity that implicitly underpins such approaches--self-other, adult-infant, subject-object. Instead, it demonstrates the generativity of concepts of "assemblage," "event," "line of flight," in rethinking what should form the focus for the theorising, pedagogy and practices surrounding infants and toddlers. To that end, it assembles a description of mealtime, a common segment of the lives of four young children in an Australian Family Day Care home. The assemblage connects a variety of heterogeneous elements, human and non-human, animate and inanimate, including highchairs, bottles, researchers, technologies, ideas, regulations, food, gravity and our own attempts to enunciate and engage with mealtime. It is concluded that, through the relations afforded by and made between these diverse elements, the descriptions of mealtime show how highchairs and their allies may afford a new infant-world symbiosis that entails not just a time and place to eat, but access to unanticipated relations of power, opportunities for connection, and ways of becoming. Such is the "what" that should inform theorising, practice and pedagogy involving very young children. (Contains 1 figure.)