Śatapatha Brāhmaṇa ("of a hundred paths") 6.3.3.18

6.3.3.18

ājyena juhoti | vajro vā ājyaṃ vajramevāsmā etadabhigoptāraṃ karotyatho reto vā ājyaṃ reta evaitatsiñcati sruveṇa vṛṣā vai sruvo vṛṣā vai retaḥ siñcati svāhākāreṇa vṛṣā vai svāhākāro vṛṣā vai retaḥ siñcati

He offers with ghee; for the ghee is a thunderbolt: he thus makes the thunderbolt its (or his, Agni's) protector. The ghee, moreover, is seed: he thus pours forth seed,--with the sruva-spoon; for the sruva (m.) is a male, and the male pours forth seed,--with 'Svâhâ (hail!),' for the Svâhâkâra (m.) is a male, and the male pours forth seed.