The Grihya Sutras, Part 1 (SBE29), by Hermann Oldenberg, , at sacred-texts.com
1. In the third year the Kaula (i.e. the tonsure of the child's head), or according to the custom of the family.
2. To the north of the fire he places vessels which are filled respectively, with rice, barley, beans, and sesamum seeds;
3. To the west (the boy) for whom the ceremony shall be performed, in his mother's lap, bull-dung in a new vessel, and Samî leaves are placed.
4 4. To the south of the mother the father (is seated) holding twenty-one bunches of Kusa grass.
5. Or the Brahman should hold them.
6. To the west of (the boy) for whom the ceremony is to be performed, (the father) stations himself and pours cold and warm water together with (the words), 'With warm water, O Vâyu, come hither!'
7. Taking of that (water), (and) fresh butter, or (some) drops of curds, he three times moistens (the boy's) head, from the left to the right, with (the formula), 'May Aditi cut thy hair; may the waters moisten thee for vigour!'
8 8. Into the right part (of the hair) he puts each
time three Kusa bunches, with the points towards (the boy) himself, with (the words), 'Herb! protect him!'
9. (With the words,) 'Axe! do no harm to him!' he presses a copper razor (on the Kusa blades),
10. And cuts (the hair) with (the verse), 'The razor with which in the beginning Savitri the knowing one has shaved (the beard) of king Soma and of Varuna, with that, ye Brâhmanas, shave now his (hair), that he may be blessed with long life, with old age.'
11. Each time that he has cut, he gives (the hairs) with their points to the east, together with Samî leaves, to the mother. She puts them down on the bull-dung.
12. 'With what Dhâtri has shaven (the head) of Brihaspati, Agni and Indra, for the sake of long life, with that I shave thy (head) for the sake of long life, of glory, and of welfare'thus a second time.
13 13. 'By what he may at night further see the sun, and see it long, with that I shave thy (head) for the sake of long life, of glory, and of welfare'thus a third time.
14. With all (the indicated) Mantras a fourth time.
15. Thus three times on the left side (of the head).
16 16. Let him wipe off the edge of the razor with (the words), 'If thou shavest, as a shaver, his hair with the razor, the wounding, the well-shaped, purify his head, but do not take away his life.'
17. Let him give orders to the barber, 'With lukewarm water doing what has to be done with water, without doing harm to him, arrange (his hair) well.'
18 18. Let him have the arrangement of the hair made according to the custom of his family.
19. The rite only (without the Mantras) for a girl.
184:4 He cuts off the hair four times on the right side (Sûtras 10-14), three times on the left side (Sûtra 15); each time three Kusa bunches are required. This is the reason why twenty-one bunches are prescribed.
184:8 Each of the four times and of the three times respectively that he cuts off the hair; see the preceding note.
185:13 Instead of yena bhûyas ka râtryâm, Pâraskara (II, 1, 16) has, yena bhûris karâ divam.
185:16 Comp. Pâraskara II, I, 19; Atharva-veda VIII, 2, 17.
186:18 On these family customs, see Grihya-samgraha-parisishta II, 40; Roth, Zur Literatur and Geschichte des Weda, p. 120; Max Müller, History of A. S. L., p. 54 seq.; Weber, Indische Studien, X, 95.