SB 10.88.25-26

ajānantaḥ prati-vidhiṁ
 tūṣṇīm āsan sureśvarāḥ
tato vaikuṇṭham agamad
 bhāsvaraṁ tamasaḥ param
yatra nārāyaṇaḥ sākṣān
 nyāsināṁ paramo gatiḥ
śāntānāṁ nyasta-daṇḍānāṁ
 yato nāvartate gataḥ
Synonyms: 
ajānantaḥ — not knowing; prati-vidhim — counteraction; tūṣṇīm — silent; āsan — remained; sura — of the demigods; īśvarāḥ — the lords; tataḥ — then; vaikuṇṭham — to Vaikuṇṭha, the kingdom of God; agamat — he came; bhāsvaram — luminous; tamasaḥ — darkness; param — beyond; yatra — where; nārāyaṇaḥ — Nārāyaṇa; sākṣāt — directly visible; nyāsinām — of sannyāsīs; paramaḥ — the Supreme Lord; gatiḥ — goal; śāntānām — who are peaceful; nyasta — who have renounced; daṇḍānām — violence; yataḥ — from which; na āvartate — one does not return; gataḥ — having gone.
Translation: 
The great demigods could only remain silent, not knowing how to counteract the benediction. Then Lord Śiva reached the luminous realm of Vaikuṇṭha, beyond all darkness, where the Supreme Lord Nārāyaṇa is manifest. That realm is the destination of renunciants who have attained peace and given up all violence against other creatures. Going there, one never returns.
Purport: 

According to Śrīla Śrīdhara Svāmī, Lord Śiva entered the planet of Śvetadvīpa, a special outpost of the spiritual world within the confines of the material universe. There, on a beautiful white island surrounded by the celestial Ocean of Milk, Lord Viṣṇu rests on the serpent bed of Ananta Śeṣa, making Himself available to the demigods when they need His help.