[Shampoo]

If you don't have much times on your hand, why don't you consider Binaural Beats or massage?

Binaural Beats are sounds that you listen to that does something to the brain to create the desired effect. Sorry that my explanation is not exactly scientific but I don't know much about the subject.

Here are a couple of Binaural Beats I listen to:

https://www.youtube.com/watch?v=RRiMqu6TMzk

https://www.youtube.com/watch?v=2UIuhsoV60g

Hope this helps.