Lord Vishnu takes rest on Sheshnag during the whole period of Uttarayan, which begins just after the last day of the bright lunar phase in the Hindu month of Ashadh is over. After he goes to sleep, all the deities, Gandharva, Devamata etc. follow suit.
Narada requested Sage Pulastya to shed light on the days when the deities take rest. Sage Pulastya replied- “A devotee should consider the eleventh day of the Hindu month of Ashadh Shukla Paksha, when the Sun enters the zodiac of Gemini as the day when Lord Vishnu goes to rest. A devotee should make a replica of Sheshnag and after worshipping the idol of Lord Vishnu, lay him down to rest on the twelfth day. Kamadev is said to take rest on the thirteenth day on his bed made of Kadamb flowers. The Yakshaganas take rest on the fourteenth day of the Hindu month of Ashadh Shukla Paksha. Their beds are made of yellow lotus. Lord Shiva is believed to take rest on Purnima. His bed is made of tiger skin.