Jaiminīya Upaniṣad Brāhmaṇa 3.5.5

3.5.5

bahiṣpavamānam āsadya ṭītra viyi prāṇya iti kūryāt ṭītra gṛhitra apānya iti vācā
didṛkṣetaivākṣibhyaṃ śuśrūṣetaiva karṇābhyām
svayam idam manoyuktam /

Having approached the bahiṣpavamāna, he should breathe in [with the sound] "ṭītra viyi", and breathe out with speech [saying] "ṭītra gṛhitra".
He should desire to see with both eyes; he should desire to hear with both ears;
this [chant] is spontaneously yoked to the mind.