When a person is driving while listening to music, and rhythmically thumping on the steering wheel, as if playing the drums to the beat of the music. Most often observed at stop lights; also the person's lips are normally viewed attempting to sing or mouth the words to the song. On rare occasions, you may actually hear the person's voice and/or hear the 'thumps' of them drumming the steering wheel. On very rare occasions the person will close their eyes and raise their neck up to emphasis a high note , thus sitting at the stop light, even after the light turns green.