This study explores how siblings in Tanzania actively engage in their own socialization through the negotiation and local design of caregiving practices and control between younger siblings (age 1–3), older siblings (age 3–13) and adults. Analyses of moment-to-moment embodied, multimodal sequences of interaction illustrate how caregiving responsibility is negotiated. The analysis is multidisciplinary drawing on concepts developed in the traditions of sociology, language socialization and applied linguistics. The findings highlight the usefulness of a concept of socialization which recognizes the agency of the child and are discussed in relation to constructions of the caregiving child as both being and becoming.