This mantra is a variation of another similar mantra for the same purposed published some time back- that mantra can be seen - HERE. The Tantra prescribe for the practice of this mantra for gaining Siddhi is weird and would appear somewhat strange, yet, I will explain this procedure.
On any auspicious Hindu date or festival, the practitioner has to commence the Mantra experiment by standing or sitting without any clothes on his body. Then he has to hold his Private Part in his right hand and chant this mantra 1008 times. He should use a Rudraksha Mala and use his left hand to count the number of Mantra Chants.
Vacha Siddhi and what he speaks from the bottom of his heart will come true.
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