Ishan Shivanand ji, an exponent of Advance Intensive Prati Prasav sadhna describes it in one word as ‘Shuddhi’ or purification. 
This intensive meditation programme involves 
1) Clearing the backlog of negativity
2) Unburdening the accumulated emotional garbage.
3) The power of the sacred mantras combine with Shiv Yog Shakti to add a new, welcome and refreshing addition of divinity in life.
4) Through parables from Enlightened Guru His Holiness Avdhoot Shivanand ji’s life during the discourses, Ishan ji gives an entirely new perspective on Shiv Yog teachings

5) Relaxation and activation of the mind to develop creativity and a scientific temperament which greatly helps in understanding the cosmic philosophy of spiritual science

‘Prati Prasav’ implies new birth. But this Shiv Yog meditation is anything but the commonly understood past life regression therapy. The latter involves hypnosis and people often live their fantasies and hallucinate during the process. Shiv Yog Guru Avdhoot Shivanand ji says that the motive of man taking birth is to get rid of all his negative psychic impressions. These impressions are nothing but pent-up emotions of anger, greed, jealousy, resentment, sorrow, jilt, unforgiveness etc. The piling up of these negative emotions results in their manifesting as disease. It is said that time heals. In reality time doesn’t heal. It just makes us forget the problem, just like brushing something underneath a carpet. The gloom of present has its root in the past. So clearing the backlog of negative karmas is the only solution to seek a lasting solution to various kinds of problems of the present. Moreover, in order to attain the state of Self-Realization, one has to clear the vast storehouse of these negative karmas in our subtle bodies. The Shiv Yog Cosmic energy, when it rains on the sadhak, he is made to go through a process in which he re-lives the incidents which have had a strong impact on the psyche and due to which his current behavior is being influenced. And as the emotions emerge on the surface, the cosmic energy nullifies them, mellows them down and slowly burns them completely.

The advance intensive level of this sadhna aids 
1) The release of pent up anger, resentment, fear and hatred
2) Facilitates inscription of virtues such as forgiveness, acceptance and unconditional love in the soul
3) In modern spirituality, seekers treat it is an ablution ritual before plunging in the ocean of cosmic energy in big-bang meditations.
4) Access to and release of the deep hidden negative memoirs of past and current births
5) Shedding of this heavy load of samskaras and bringing out the inner light in the form of health, happiness & prosperity.
6) Attainment of a higher level of spirituality
7) Experience of the Ultimate Truth by releasing these psychic impressions
8) Awakening of your consciousness towards infinite dimension