The mouth is the most primal musical instrument and a central interface for wind performance, yet it remains largely overlooked in the design of contemporary electronic instruments. Given its exceptional sensory acuity and fine motor control, this neglect represents a loss of expressive potential and a hindrance to musicians with motor disabilities. This paper documents a participatory workshop on electronic mouth-only instruments, co-led by an expert with tetraplegia. Grounded in Tangible Musical Interface design, our approach emphasises sensorimotor interactions to reconnect digital sound creation with embodied experience. To support the playful exploration of this design space, we developed a modular toolset combining electronic input and feedback modalities for the mouth, along with methods for custom-built accessibility devices.