This paper presents the concept, design, and experimental implementation of a Balance Feedback Interface (BFI) for human-in-the-loop control of a humanoid robot. The purpose of the BFI is to create a new media to aid the task of bilateral feedback during full-body teleoperation of humanoid robots. It explores human's primitive motor skills to enhance the dynamic behavior of the slave platform to a performance level comparable to humans. This project aims to leverage legged robot's performance to respond to disaster situations such as nuclear, fire, or chemical hazards. We expect to reliably deploy a legged platform to a dangerous environments and perform powerful manipulation tasks such as hammering/axing, moving/lifting heavy objects, etc. Initial results show that the human can react to disturbances on the humanoid robot while performing an upright balancing task. We believe this is the key technology that allows for the paradigm shift from quasi-static regime to truly dynamic performance of humanoid robots.