The Bass Sleeve uses an Arduino board with a combination of buttons, switches, flex sensors, force sensing resistors, and an accelerometer to map the ancillary movements of a performer to sampling, real-time audio and video processing including pitch shifting, delay, low pass filtering, and onscreen video movement. The device was created to augment the existing functions of the electric bass and explore the use of ancillary gestures to control the laptop in a live performance. In this research it was found that incorporating ancillary gestures into a live performance could be useful when controlling the parameters of audio processing, sound synthesis and video manipulation. These ancillary motions can be a practical solution to gestural multitasking allowing independent control of computer music parameters while performing with the electric bass. The process of performing with the Bass Sleeve resulted in a greater amount of laptop control, an increase in the amount of expressiveness using the electric bass in combination with the laptop, and an improvement in the interactivity on both the electric bass and laptop during a live performance. The design uses various gesture-to-sound mapping strategies to accomplish a compositional task during an electro acoustic multimedia musical performance piece.