Kokong is an immersive and participant-driven performing arts experience that explores the physical and emotional landscape of trust through rope binding, biodata, haptics, light and sound. This thesis focuses on one part of the final production: the interaction design of two cocoons in which participants will be suspended and connected to audience participants via technological “umbilical cords”. Through research through design, first-person embodied inquiry, materials exploration, interviews, prototype testing, and software sketching, the thesis investigates how physiological data from participants can be captured, processed, and transmitted into a responsive system for live performance. The resulting design combines ECG, PPG, and GSR sensors with haptic feedback, capacitive rope, Max/MSP-based signal processing, and networked communication with light and sound systems. Beyond the technical system, the thesis examines what contribution interaction design can make to navigating trust in this context, arguing that biodata can be treated as a relational and dramaturgical material through which trust, vulnerability, and connection can be explored.