The Sacred ash, Vibhuti is to be applied between the eyebrows, known as agna chakra, at the pit of the throat, known as vishuddhi chakra and in the center of the chest where the ribcage meets, known as the anahata chakra.
Vibhuti is applied at the agna so that you receive life as knowledge. It is applied at the vishuddhi so that you receive life as power. Vibhuti is applied at the anahata so that you receive life as love.
Isha Vibhuti is consecrated by leaving in the Dhyanalinga temple for a period of time wherein it is specially blessed by Dhyanalinga.
In Indian culture, Vibhuti has been looked at deeply as a tool for a person’s growth. Properly prepared sacred ash has a different vibrancy. If the Vibhuti is properly prepared and if one knows where and how to apply it, sacred ash makes one much more receptive; and the place where one applies it on their body becomes more sensitive and goes towards the higher nature.
Now this powerful vibhuti here, when you take it with your ring finger, unknowingly you will drop some karma right here. The whole tradition was built like that - whichever way, you must be slowly moving towards your liberation. - Sadhguru
Read the science behind vibhuti, the sacred ash.