SB 8.12.24

evaṁ tāṁ rucirāpāṅgīṁ
 darśanīyāṁ manoramām
dṛṣṭvā tasyāṁ manaś cakre
 viṣajjantyāṁ bhavaḥ kila
evam — in this way; tām — Her; rucira-apāṅgīm — possessing all attractive features; darśanīyām — pleasing to see; manoramām — beautifully formed; dṛṣṭvā — seeing; tasyām — upon Her; manaḥ cakre — thought; viṣajjantyām — to be attracted by him; bhavaḥ — Lord Śiva; kila — indeed.
Thus Lord Śiva saw the woman, every part of whose body was beautifully formed, and the beautiful woman also looked at him. Therefore, thinking that She was attracted to him, Lord Śiva became very much attracted to Her.

Lord Śiva was observing every part of the woman’s body, and She was also glancing at him with restless eyes. Thus Śiva thought that She was also attracted to him, and now he wanted to touch Her.