Brush your teeth
This is a very well known action that we do each day. We spent 3 to 4 minutes in front of the mirror, moving our hand to clean our teeth, but we are not conscious about what we are doing. We never spent those 3 minutes thinking about our teeth, it is such a learned action that are not fully conscious about the action.  Dentist recommend brushing your teeth 3 times a day and make it a very carefully process.
The idea is to create a toothbrush with a photosensitive sensor and speakers. This toothbrush is special it will be smaller and depending on the tooth that is cleaning, it will produce a musical note, so when you move the toothbrush in your mouth, you will be creating music.