Movement-based interactions are gaining traction, requiring a better understanding of how such expressions are shaped by designers. Through an analysis of an artistic process aimed to deliver a commissioned opera where custom-built drones are performing on stage alongside human performers, we observed the importance of achieving an intercorporeal understanding to shape body-based emotional expressivity. Our analysis reveals how the choreographer moves herself to: (1) imitate and feel the affordances and expressivity of the drones' 'otherness' through her own bodily experience; (2) communicate to the engineer of the team how she wants to alter the drones' behaviors to be more expressive; (3) enact and interactively alter her choreography. Through months of intense development and creative work, such an intercorporeal understanding was achieved by carefully crafting the drones' behaviors, but also by the choreographer adjusting her own somatics and expressions. The choreography arose as a result of the expressivity they enabled together.