Mudgalapurana 3.18.10

3.18.10

tarjanyādyaṅgulībhiśca tisṛbhiḥ saṃspṛśen mukham |
tarjanyaṅguṣṭhayogena nāsikāṃ saṃspṛśed budhaḥ ||

With the three fingers beginning with the forefinger he should touch the mouth; / with the union of the forefinger and thumb the wise man should touch the nose;