It is believed that on Mannarasala Ayilyam nakshatra day, Sree Nagaraja who resides in the nilavara of the illam gives darshan to the Mannarasala Amma or the main priestess of the temple.
The most important event on Mannarasala Ayilyam is the ezhunnallathu after ucha pooja. The murtis of Nagaraja, nagayakshi and other naga deities are carried in a procession to the Thekke Thalam in the Illam.
The main Nagaraja worshipped in the temple is in Vasuki Sankalpam. In the northside of Nagaraja shrine is the shrine of Nagayakshi Amma.
The temple opens on Ayilyam nakshatra day at 4:00 AM - the main rituals at this time are nirmalyam and abhishekam.
After this special pujas is performed to Nagaraja and Sarpa Yakshi by adorning them with Thiruvabharanam or special gold ornaments.
The pujas in the temple are Shaiva in nature and the sankalpam of Nagraja is that of Vasuki.
Legend has it that Lord Parashurama had appointed a priest from the Mannarasala Illam (a Brahmin home is referred to as illam in Kerala) at Sree Nagaraja Temple . The family still continues to look after the temple. Once a major fire broke out in a forest near Mannarasala village and several snakes were hurt. A childless couple in the family looked after the snakes and took care of them. Pleased with their devotion, Sree Nagaraja blessed them with twins. One child was Sree Nagaraja himself – a five hooded snake. After few years He took Samadhi. It is believed that He still lives in the cellar in Mannarasala Illam.
Before disappearing, Sree Nagaraja gave advice regarding the pujas and rituals to be followed at the temple to His mother and appointed her the priest of the temple. The main priest in the family is known as Valliamma.
Mannarasala Ayilyam is observed in the Malayalam month of Thulam (October – November). The festival is associated with the visit of the erstwhile Travancore Royal family to the Temple . It is believed that worshiping on the day will help in removing all sorts of Sarpa Dosha and childless couples will be blessed with children.
Ayilyam is one of the nakshatras, or stars, and it is believed that the ideal day to propitiate nagas or snakes is the Ayilyam nakshatra day.