The affix ṇamul comes after the roots 1. pīḍ 'to press' 2. ruddh 'to obstruct' 3. kṛṣ 'to draw' when they are preceded by the preposition upa and when they are compounded with nouns ending with the Locative -7th case-affix.,
The phrase '3rd case-affix' must be read into the sutra by virtue of the word च । Thus पार्श्वोपपीडं शेते 'he sleeps pressing on his sides'. The compounding is optional 2.2.21; so we have in the alternative, पार्श्वयोरुपपीडम् or पार्श्वाभ्यामुपपीडम् ।
So also व्रजोपरोधम् (or व्रजे उपरोधम् or व्रजेनोपरोधम्) गाः स्थापयति 'he stations the cows so that they are all in the fold'. पाण्युपकर्षं (or पाणावुपकर्षम् or पाणिनोपकर्षम्) धानाः सङ्गृह्णाति । It is Bhvadi कृष् here, and not Tudadi.,