Agniveshyagrihyasutra 2.6.1.2

2.6.1.2

prāṅmukha udaṅmukho vā dvau pāṇī prakṣāḷya baddhaśikho yajñopavītī jale vātha sthale vāntarjānu navivarāṅguḷībhiḥ gokarṇākṛtivat karaṃ kṛtvā tiṣṭhan na praṇato na hasanna jalpan na vrajan noṣṇābhirna vivarṇābhirna budbudābhiḥ na calo jalaṃ māṣamagnamātraṃ pibet \

Facing east or facing north, having washed both hands, with his topknot bound, wearing the sacred thread, in water or on land, between the knees, with fingers without gaps, having made the hand like the shape of a cow's ear, not standing, not bending down, not laughing, not chatting, not walking, not with hot [water], not with discolored [water], not with bubbly [water], not moving, he should drink an amount of water just sufficient to submerge a māṣa bean.