Hi Tamasaburo,
The only thing to do during meditation is to stick to the procedure that is meant to be used during this time. So if you are following AYP Deep Meditation, then sticking to the procedure of returning to the mantra when we notice we are off of it. This is what brings about lasting change on so many levels.
Spending time on contemplating what "mental blockages or suppressions" that
might be lurking inside our minds only detracts from the process and slows the progress. There is plenty of time to do this during the rest period or during the day between practice sessions. If you are following a powerful system of practices like AYP the blockages that are limiting the full expression of our inner energy will soon become apparent one by one. Life is the primary teacher and practices make the lessons a lot easier and help them to pass more quickly.
When particular issues or thoughts that are limiting present themselves in my life, I will often take the time outside of sitting practices to inquire into them in order to accelerate the letting go process that can come from true understanding. It is like a ball of yarn, every time we lift a thought which could be represented by a piece of string from the ball, we allow the energy to flow more freely. Eventually all the thoughts are lifted away (all the pieces of string) and there is no ball left to speak of and the energy is flowing freely.
So looking for a particular thought or mental blockage that might be holding kundalini back from expressing throughout the body would be missing the point from my perspective. By systematically, twice each day, practicing meditation, pranayama, tantra and inquiry etc., vast numbers of mental blockages will be cleared away and the energy will be flowing much more freely as a result in due course.
When "kundalini" opens up, it is just another step along the way. What really is of consequence is the mental freedom, peace and inner happiness that increases slowly over time with each day of practice. Inner silence is what is the most revealing aspect of our true nature and the true nature of the universe around us.
Hope this helps[
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