Rubbing in-breath and out-breath, like rubbing two sticks, will make heat and make a fire. This “fire” becomes visible as light between the eyebrows.

One is to “place the maiden” (reveal the Kutastha) in the circle (circular light between the eyebrows) and pierce that Yoni (retire within it). It is Kriya. It is learned from the mouth of the Guru.

Salutations,

bala