So Hum is a simple and powerful meditation practice anyone can try.  How about right now?

To begin, choose a place where you won’t be disturbed. Sit in a chair or on the floor, using blankets and pillows to make yourself as comfortable as possible.

Close your eyes and for a few minutes and observe the inflow and outflow of your breath.
Take a slow, deep breath through your nose, while thinking or silently repeating the word So.
Then slowly exhale through your nose while silently repeating the word Hum. Continue to allow your breath to flow easily, silently repeating So . . . Hum . . . with each inflow and outflow of the breath.

Whenever your attention drifts to thoughts in your mind, sounds in the environment, or sensations in your body, gently return to your breath, silently repeating So . . . Hum.
Do this process for two minutes. Just breathe easily and effortlessly, without trying to concentrate. When the time is up, sit with your eyes closed for a few moments.
When you try this exercise, you probably will notice that just by focusing on the sounds So Hum, you sink deeper into relaxation as your mind quiets. You may also experience a few moments of complete silence.

Check more out here.