Gobhilagrihyasutra 4.10.6

4.10.6

yā oṣadhīr ity udañcaṃ viṣṭaram āstīryā 'dhyupaviśet;

Let him spread out the bed (of grass, so that the points of the grass are) turned to the north, with (the verse), 'The herbs which' (MB. II, 8, 3), and let him sit down thereon;