Recent voices in creativity research emphasize the vital role that processes of active engagement and interaction play. These distributed, interactivity-based, and ecological accounts critique the reduction of creativity to mental mechanisms and eschew the methodological individualism that underlies this view. Instead, they elevate socio-material couplings to a genuine causal mechanism, hereby explaining why others "are good to be creative with" beyond mutual inspiration or mere constraints on creativity. With improvised dance duets as our example, we introduce a micro-analysis that unpacks these mechanisms from a first-person viewpoint: We describe how the embodied communication at the sub-second scale, a continuous "give and take" between dancers, mediates the co-creation process and how reciprocal micro-actions cumulate into more complex creative effects. Secondly, we distinguish convergent and divergent co-creation dynamics, degrees of playful exploration vs. adaptive pressures, and degrees of individual creative autonomy. Thirdly, we argue that the mix of external constraints, joint exploration, and individual ideation provides a fertile mechanism for co-creation. Finally, we discuss forms of individual creative vision that respect and exploit the dynamic ecology, which can manifest in immediate micro-inspirations, but also in subtle modulations of ongoing process, and in "cultivating" the wider system in ways that benefit novelty.