Lahiri Mahasaya described everything in relation to Kutastha. Every paragraph of Manu smruti, upanishads, vedas all relate to the Kutastha. He constantly talked about being established in Kutastha
Vishnutirthji Maharaj – who has showered innnumerable grace and blessings – described Kutastha – Kuta meaning pile of prana and stha meaning established.
Gorakshnatha went a little more and described layers within Kutastha.
So the entire process of awakening and Yoga is related to Kutastha. It goes by other names too. Since the other names are specific to each lineage, I will not describe the names from all the different lineages
In my lineage, which is all encompassing, all aspects of all lineages are covered, Gurudev would change name based on the level of the disciple.
Where is this located? Above the Agna chakra. This still remains somewhat ambiguous since there are a few levels between Agna chakra and Sahastrar. This place is the source of various Siddhis which appear automatically and effortlessly. No book can describe all the glory or merit of Kutastha.
Every lineage has a different secret which they use to merge into Kutastha. This trick or secret has been written all over and everyone knows them. Then how can it be a secret. It is a secret since people only the the words but how the word is implemented in Yoga is totally unknown. For that it takes years of practice, patience, increasing purity and the loving Krupa of your Guru. It is at this level, Ramkrishna Paramhansa said all paths are the same. He tried the secret from a variety of different religions and in less than a minute reached Kutastha. So the difference in religions is a trivial matter.
A Guru is someone who is fully cognizant of this chakra.