Manava Dharmashastra 4.75

4.75

astamite āditye | pratilakṣaṇe karmapravacanīyatvāt dvitīyā | na cocchiṣṭaḥ | "nanu ca brahmacaryadharmeṣvetatpratiṣiddham | puruṣadharmatā ca tasya jñāpitā | na tādarthyameva” | satyam | vratarūpatājñāpanārtha upadeśo'yam | tena yāvajjīvikaḥ saṃkalpaḥ kartavyaḥ |

Any food containing sesamum, he shall not eat after sunset; he shall never sleep naked; nor go anywhere with mouth unwashed after meals.—(75)

Medhātithi’s commentary (manubhāṣya):
On the sun having set; the accusative ending in ‘astam’ is in accordance with Pāṇini 1. 4. 90.

‘Nor go anywhere, etc.’—“This has already been forbidden in the section dealing with the duties of the Student; where it has been also explained that the prohibition pertains to the men in general, and is not restricted to the Student only.”

True; but the present injunction is for the purpose of pointing out the act as an ‘observance;’ and what is meant is that ‘One should make a life-long determination of not going about with mouth unwashed after meals.’—(75)

This verse is quoted in Saṃskāramayūkha (p. 72).

Comparative notes by various authors
Gautama (9.60).—‘He shall never sleep naked at night.’

Viṣṇu (69.29).—‘At night, he shall not eat anything mixed with sesamum.’

Viṣṇu (70.3).—‘Nor naked (shall he sleep).’

Āśvalāyana Gṛhyasūtra (3.9.6).—‘He shall not bathe during night; he shall not bathe naked; he shall not sleep naked; he shall not look at a naked woman, except......’