Śatapatha Brāhmaṇa ("of a hundred paths") 5.4.4.4

5.4.4.4

athainamāsādayati | syonāmāsīda suṣadāmāsīdeti śivāṃ śagmāmāsīdetyevaitadāha kṣatrasya yonimāsīdeti tadyaiva kṣatrasya yonistasyāmevainametaddadhāti

He then makes him sit down on it, with, 'Seat thee on the pleasant one! seat thee on the soft-seated!'--whereby he says, 'Seat thyself on the kindly and auspicious (seat)!'--'Seat thee in the womb of knighthood!'--thus he places him in what is the very womb of knighthood.