The works of Ādi Śaṅkarācārya

Bṛhadāraṇyakopaniṣadbhāṣyam

Bhashya

Bhashya

अथास्य दक्षिणं कर्णमभिनिधाय स्वं मुखम् 'वाग्वाक्'इति त्रिजपेत् ।अथ दधि मधु घृतं संनीय अनन्तर्हितेन अव्य-वहितेन जातरूपेण हिरण्येन प्राशयति एतैर्मन्त्रैः प्रत्येकम् ॥

In plain words

He brings his mouth right up to the child's right ear and quietly says 'Vāk, Vāk' three times. Then he mixes curds, honey, and ghee, and feeds the child pure, unblended gold — with a mantra spoken for each act.

Close to the Sanskrit

Then, having placed his own mouth close to this [child's] right ear, [saying] 'Vāk, Vāk,' thus, he should mutter thrice. Then, having brought together curds, honey and ghee, he feeds [him] with undivided, unmixed native gold — with these mantras, for each one.