I have vibrated my chakras before falling asleep. The vibrations actually put me to sleep.
Also, vibrating my whole back.
Sometimes I use a mantra, and other times I just imagine hearing and feeling a buzzing sound.
Some hotels have beds that you can put some quarters in ( here in America ), and the bed vibrates for a few minutes.
I get results just using my mind.
It is a lower octave pitch in the vibrations.