Skandapurana 16.277.5

16.277.5

dakṣiṇāhṛdayo yogī mahāsatraśayo mahān ..
upākarmoṣṭharucakaḥ pravargyāvartabhūṣaṇaḥ .. 5 ..

having the sacrificial fee as His heart, a yogin, reposing in the great Soma sacrifice, the Great One, / having the upākarman ceremony as the beauty of His lip, adorned with the whirlpool of the pravargya rite;