On-body sensing has been extensively explored by researches in the past decade. In this work, we present NecX, using neck as an input device. The system exploits surface Electromyography (sEMG) to detect the intensity of neck muscle. Our system captures the conducted current flowing through our sensor when the muscle is stressed, and uses the signal variations to identify a neck gesture. In our current prototype, we designed 5 neck gestures including rotation and tilt, etc. We implemented a real-time system to apply NecX in the gaming control.