Manava Dharmashastra 3.196

3.196

śucirbhasmāsthikapālakādyanupahataḥ | vivikto vistīrṇo bahubhirjanairanākīrṇaḥ | dakṣiṇāpravaṇo dakṣiṇasyāṃ diśyavanataḥ | tādṛśaṃ deśaṃ yatnena sampādayet | svabhāvataścettādṛśo na labhyate tathā kartavyaṃ yathā svavyāpāreṇa sampādyate |
taṃ ca gośakṛtāepalepayet | mṛdādayo nivartante, gomayenopalepaniyamāt |

One should prepare with care a clean and secluded place Sloping towards the south, and smear it with cowdung.—(206)

Medhātithi’s commentary (manubhāṣya):
‘Clean’— not defiled by the presence of ashes, bones, skulls, and such things.

‘Secluded’—large and unoccupied by many men.

‘Sloping towards the south’—that which is of lower level on the southern side. Such he should make the place, ‘with care.’ That is, if one fails to find a spot that is not naturally so, one should make it so, by one’s own effort.

This place he should smear with cowdung. This precludes the use of clay and such things, the rule being that the smearing should be done with cowdung.—(206)