The scriptures which say "Aham Brahmasmi," or "I am that", or "You are that," do not mean any physical location to meditate upon, when the phrase "the cave of the heart" comes.

What do you think? Guru feels, "the cave of the heart" refers to be just "here and now," in the present moment, that is eternity itself, and everything happens in this eternity. The "here and now" is very auspicious, all the awakening happens in this moment. And, it will not lead something into past and something into future; it will put you as you are, in the most potent form.

"The cave of the heart," doesn’t give you any mantra to chant open or any object to concentrate upon, it is just simple and powerful, to be just in "here and now," in the present moment, where all flowers blossom.