Param-dhyana is mentioned in the "Tejobindu Upanishad," which emphasizes the importance of meditation. It says that for a yogi in param-dhyana, their focus should be on the source of all spiritual light, or the seed, which the text refers to as Tejo-bindu. It is said that this seed is the size of an atom and is located in the heart. It is both gross and subtle and it pertains to Shiva.
When a yogi achieves param-dhyana, it is said that they lose all desires
and all boundaries and are no longer constrained by natural laws. Some sources emphasize the fact that, unlike other meditation techniques or spiritual practices, there is no need for self-denial or austerities to engage in param-dhyana. Instead, it is a natural pattern that works with the mind, body and soul to achieve Self-realization.