Śatapatha Brāhmaṇa ("of a hundred paths") 3.3.2.19

3.3.2.19

atha somopanahanasya samutpāryāntān | uṣṇīṣeṇa vigrathnāti prajābhyastveti prajābhyo hyenaṃ krīṇāti sa yadevedaṃ śiraścāṃsau cāntaropenitamiva tadevāsyaitatkaroti

He then makes a finger-hole in the middle (of the knot), with the text, 'Let the descendants breathe after thee!' For, in compressing (the cloth), he, as it were, strangles him (Soma and the sacrificer) and renders him breathless; hereby now he emits his breath from inside, and after him breathing the descendants also breathe: for this reason he says, 'Let the descendants breathe after thee.' Thereupon he hands him (Soma) to the Soma-seller. Now, then, of the bargain.