Shivashayanotsavam
Vamana Purana says
Paurṇamāsyāmumānāthaḥ svapatē carma sanstarē ||
vaiyāghrē ca jaṭābhāraṁ samudgradhyāhivartmaṇā ||
According to belief, lord Shiva sleeps for four months from full moon day of the Ashada month. On that day, Shiva shayanotsavam will be celebrated. on Ashada purnima day devotees perform pradosh kaal puja and observe Rudra Vratham.
It should be noted that both Lord Shiva and Lord Vishnu go to sleep in the same month i.e Ashadam.
