Tantrasara (Krishnananda) 2.p505

2.p505

prātaḥkṛtyādi durgāmantroktaṃ ṛṣyādinyāsāntaṃ karmaṃ kṛtvā
karāṅganyāsau kuryāt .
oṃ durge aṃguṣṭhābhyāṃ namaḥ, durge tarjanībhyāṃ svāhā,
durgāyai madhyamābhyāṃ vaṣaṭ, bhūtarakṣaṇi anāmikābhyāṃ
huṃ, oṃ durge durge akṣaṇi kaniṣṭhābhyāṃ vauṣaṭ, oṃ durge durge
rakṣaṇi karatalapṛṣṭhābhyāṃ phaṭ hṛdayādiṣu .. 14ka ..

Having performed the rites beginning with the morning rites up to the placement of the seers and others as stated in the Durgā mantra, one should perform the placements on the hands and limbs.
"oṃ durge", to the thumbs, namaḥ; "durge", to the forefingers, svāhā; "durgāyai", to the middle fingers, vaṣaṭ; "bhūtarakṣaṇi", to the ring fingers, huṃ; "oṃ durge durge akṣaṇi", to the little fingers, vauṣaṭ; "oṃ durge durge rakṣaṇi", to the palms and backs of the hands, phaṭ; [and likewise] on the heart and other [limbs]. (14a)