The study focuses on the mechanisms through which dance brings people together. We recorded 7 improvised dance duets and asked 5 skilled improvisers to rate the perceived togetherness in the recorded dances. Subsequently, we employed pose tracking techniques and developed a quantitative measure of the stability of interpersonal movement coordination between dancers, demonstrating that it strongly correlates with experts' togetherness ratings. Based on follow-up interviews, we revealed that experts' understanding of togetherness converges to a stable construct, involving a state of responsive, mindful attention. This construct can be grounded in the objective properties of movement coordination. These properties can be framed within the context of dynamical systems, suggesting potential systemic organization principles, such as moment-to-moment adaptation, that promote togetherness. Our mixed-methods research has implications for various fields, including psychology, cognitive science, and art studies.