Aitareyabrahmana 3.35

3.35

He begins the āgnimāruta cup recitation with [a hymn] to Vaiśvānara.
Vaiśvānara indeed made this poured-out semen stir;
therefore he begins the āgnimāruta with [a hymn] to Vaiśvānara.
The first verse should be recited without taking a breath. He who recites the āgnimāruta goes setting down [his feet] upon unappeased fires and flames;
with the breath itself he crosses over the fires.
If while reciting he should stumble, he should seek another to speak out for him;
making him a bridge, he crosses over.
Therefore there should be no stopping in the āgnimāruta; an expounder is to be sought.
He recites [a hymn] to the Maruts.
The Maruts indeed, blowing upon it, made this poured-out semen stir;
therefore he recites [a hymn] to the Maruts.
With 'At each sacrifice for your Agni' [ṚV 1.27.1] and
'The divine wealth-giver to you' [ṚV 2.5.1], he recites in the middle the womb [yoni] and the corresponding verse [anurūpa].
In that he recites the womb and the corresponding verse in the middle, therefore the womb is held in the middle.
And in that he recites them after reciting two hymns,
he places generation above the two foundations for the sake of propagation.
He is propagated with offspring and with cattle who knows thus.