The Compendium of Caraka 4.8.11

4.8.11

tataḥ putrakāmā paścimato'agniṃ dakṣiṇato brāhmaṇamupaviśyānvālabheta saha bhartrā yatheṣṭaṃ putramāśāsānā/

Then, desiring a son, sitting to the west of the fire and to the south of the brāhmaṇa, she should hold on to him together with her husband, wishing for the desired son.