Śatapatha Brāhmaṇa ("of a hundred paths") 1.9.2.14

1.9.2.14

tadiḍāntam bhavati | na hyatra paridhayo bhavanti na prastaro yatra vā adaḥ prastareṇa yajamānaṃ svagākaroti patiṃ vā anu jāyā tadevāsyāpi patnī svagākṛtā bhavatīyasi taṃ ha kuryādyatprastarasya rūpaṃ kuryāttasmādiḍāntameva syāduto prastarasyaiva rūpaṃ kriyate

This (ceremony) concludes with the idâ; for here are neither enclosing-sticks nor the prastara-bunch. For on that occasion when he wishes the sacrificer good-speed (svagâ) by (offering) the prastara, good-speed is at the same time wished to his consort also, since the wife comes (immediately) after the husband. But were he to use a substitute for the prastara-bunch, he would produce lassitude (in the wife): for this reason this (ceremony) should conclude with the idâ. Nevertheless a substitute for the prastara is (optionally) made.