What occurs in situations where a preschool teacher and a researcher provide two-year-old children a basin full of water? How would one analyze the promoted and the possible actions, together with the actions actually taking place in the here-and-now? With qualitative microanalysis of video recordings in a day care centre, this study explores how children’s actions and meaning making are bidirectionally related to the continuously (re)structured historical, cultural, social, and material context. The theoretical and methodological tools to investigate the complexity of the situations are developed on the basis of contemporary studies following the socio-cultural tradition in psychology. The study contributes to discussions on children as participants in cultural canalization and emphasizes the need for analysis in early childhood education practices on the implicit and explicit constraint structures for actions.