Bija mantras are one-syllable seed sounds that, when said aloud, activate the energy of the chakras in order to purify & balance the mind & body. I have discovered that it could be used to synchronize these seed mantras of the chakras and manipulate the subtle energy fields.
Using the Bija mantras, we could activate their corresponding chakras. We start with the Root Chakra which is resonated by the Bija Mantra LAM. As you vocalize the LAM mantra, you cup your palm on the Root Chakra and as you chant the mantra LAM you try to feel the vibration on it through your palm. Chant as many times as possible until you positively feel the vibration on your chakra with your palm.
Next, you follow up with the Sacral Chakra, place your palm there, chant the Bija mantra VAM, and feel the vibration. In ascending order, you progress to the next upper chakras – Solar Plexus with RAM, Heart Chakra with YAM, Throat chakra with HAM, Third Eye Chakra, and the Crown Chakra with OM. The Crown Chakra and the Throat Chakra seem to give off the most pronounced vibrational feeling.
After you have repeated the exercise a few times, you can chant the Bija mantras and feel the vibration of their corresponding chakras without using the palm. This method of training would enable you to sense your own chakra. As you progress further, you could also feel out the chakras of another person near to you.
I include a YouTube video on the chanting of the Bija mantras.