CRUCIAL: This article of course tells about Manasika (silent, in mind) recitation of Mantras during Yoga, not Vachika (loud) recitation. Another crucial rule: Mantra does not exist without Dhyana, so please don't forget to resort to The Dhyana of Your Adored ParaIshwari / ParaIshwara.
Question: "Which Mantras I can use while doing my Yoga and Asana complexes?"
Yoga has more relation to Shiva-Vidyas and Shiva always Sings all The Vidyas to Shreemati Uma-Devi.
And as we all belong to Shakti-Sampradayas, we cling to the Mantras of Shreemati MahaLakshmi-Devi (or Shreemati Maha Gauri-Devi) all the time.
The best Mantras for Yoga are The Mantras of Shreemati MahaLakshmi-Devi (or Shreemati MahaGauri-Devi) in Tapasvini (तपस्विनी - female ascetic)-Avataras, that is:
ॐ गौर्यै नमः
OM gauryai namaH
ॐ उमायै नमः
OM umAyai namaH
ॐ योगनिद्रायै नमः
OM yoganidrAyai namaH
ॐ योगिनीगणसेवितायै नमः
OM yoginIgaNasevitAyai namaH
All These Mantras are from
"ShrI ChAmuNDEshvarI AShTottarashataNAmAvaliH"
("108 Names of Shreemati Chamundika Ishvari") - LINK
Question: "Which Mantras you (Vishnudut1926) personally recite during your Yoga complex?"
Answer: "It depends upon my frame of mind, but as I belong to Vaishnava-Shakta-Parivara, I usually recite The Mantras of Shreemati-MahaLakshmi-Devi and Bhagavan Shree Narayana (and of course, the Mantras of Shreemati Gauri-Devi from "ShrI ChAmuNDEshvarI AShTottarashataNAmAvaliH", which I have mentioned earlier).
To be more elaborate:
1) The Mantras of Shreemati MahaLakshmi-Devi (especially the Mantra of Tapasvini-Avatara of Shreemati MahaLakshmi-Devi).
2) The Mantras of Bhagavan Shree VenkatEshwara (by the way, I have very beautiful silver amulet with my Precious Lord and Husband - http://vishnudut1926.blogspot.ru/2014/02/my-new-lockets.html
Question: "It is hard to believe that Shreemati MahaLakshmi-Devi has Tapasvini-Avatara, as we have accustomed to The Image of Shreemati MahaLakshmi-Devi being fond of Wealth, Luxury, Perfumes and all the verges of Richness".
Answer: "Shreemati MahaLakshmi-Devi is Both MahaTapasvini and MahaBhogini (as well as Bhagavan Shree Narayana).
Our Precious Ishwari comprises Contradictory Features, this Siddhanta is elaborately explained by Vaishnava-Acharyas in Their Tikas to "Shree Vedanta-Sutra" (for example, in "Shree Bhashya" By OM VishnuPad Ramanuja-Acharya or in "Vedanta-Parijata-Saurabha" by OM VishnuPad Nimbarka-Acharya and "Vedanta-Kaustubha" by OM VishnuPad Shreenivasa-Acharya - link to the Book)
Still, back to Our Tender Ishwari as MahaTapasvini - there is a Mantra of Shreemati MahaLakshmi-Devi as Tapasvini dressed in deer skin and being the role model for all Gopis-Yoginis.
This is all I can say, as one should be initiated in Shree MahaLakshmi-Vidya in order to know The Mantra.
In MahaTapasvini-Avatara Shreemati MahaLakshmi-Devi is Extremely Beautiful.
As all The Shakti-Tantras Sing: "Koti-Kandarpa-Lavanya (Koti-Kandarpa-Sundari)" - The Beauty of Shreemati MahaLakshmi-Devi shines brighter than the overall beauty of billions Rati Goddesses
