Manava Dharmashastra 2.195

2.195

pratiśravaṇamāhūyamānasya kārye niyujyamānasya gurusambandhivacanākarṇanam | sambhāṣā guruṇā sahoktipratyuktikaraṇam | te pratiśravaṇasambhāṣe | śayānaḥ sve srastare nikṣiptagātraḥ | na samācarenna kuryāt | nāsīna āsane copaviṣṭaḥ | na bhuñjānaḥ | na tiṣṭhannekasminneva deśe'vicalannūrdhva sthitaḥ | na punaḥ parāṅmukhaḥ | yasyāṃ diśi gururdṛśyate tataḥ parāvṛtya sthitirna kuryāt |

He should not listen to and converse with (his Teacher), while lying down; nor while seated, nor while eating, nor while standing, nor with his face turned away.—(196)

Medhātithi’s commentary (manubhāṣya):
‘Listen to’—i.e., listening to the words of the Teacher, when the latter calls him and directs him to do some work.

‘Converse with’—i.e., holding conversation with the teacher.

‘Listening’ and ‘conversing’ form the copulative compound ‘pratiśravaṇasambhāṣe.’

‘While lying down’;—i.e., with his body reclining upon his owa bed.

‘Na samācaret’—should not do.

‘Not while seated’—upon a seat.

‘Nor while eating, nor while stand,’—i.e., standing up right in one place, without moving.

‘Nor with face turned away’—i.e., with face averted from the direction in which the Teacher may be looking.—(195)