उमामहेश्वरव्रतं—पञ्चाक्षरमन्त्रस्य माहात्म्यं, न्यासः, जपविधिः, सदाचारः, विनियोगः
आस्येन न पिबेत्तोयं तिष्ठन्नञ्जलिनापि वा वामहस्तेन शय्यायां तथैवान्यंकरेण वा
āsyena na pibettoyaṃ tiṣṭhannañjalināpi vā vāmahastena śayyāyāṃ tathaivānyaṃkareṇa vā
不可直接以口就水而饮;亦不可站立时饮,即便以合掌掬水亦然。不可用左手饮;不可卧于床上而饮;亦不可用另一手以同样失仪之法而饮。此等戒行护持湿婆礼拜之清净,使缚魂 paśu 趋向主宰 Pati 而得安定。
Sūta Gosvāmin (narrating Purāṇic injunctions to the sages of Naimiṣāraṇya)
It teaches śauca (ritual purity) and disciplined ācāra—avoiding careless ways of drinking water—so the devotee approaches the Liṅga with reverence, restraint, and fitness for pūjā.
By implication, Śiva-tattva is approached through niyama and purity: when the pashu governs bodily habits and reduces rajas/tamas, the mind becomes steadier for turning toward the Pati, Śiva.
Pūjā-vidhi and ācāra-niyama: bodily discipline (how one drinks water) as a supportive observance that reinforces self-control aligned with Pāśupata-oriented purification.