Mannarasala covers a district of 16 acres of thick green forest grove dedicated to serpent worship. The temple here is special in that the holy rites are presided over by a priestess. The grove is spotted with the granite idols of serpents. There are 2 main idols: 'Nagaraja' or the serpent king and his consort, Sarpayakshini. The priestess lives in the 'Illam' on the north side of the temple. 'Uruli Kamazhthal' or the placing of a bell metal vessel upside down in front of the deity is the most popular offering believed to restore fertility to childless couples. On the day of 'Ayilliam' asterism in the Malayalam months of Kanni and Thulam September and October), all the serpent idols in the grove and the temple are taken in procession to illam ( the house connected with the temple) where 'Nurum Palum' (rice flour and milk), 'Kuruthi' (a red liquid made of turmeric and lime), offerings are made. The procession is conducted with great pomp and gaiety in which the oldest female member of the family carries the Nagaraja idol. During the festival days, thousands throng the temple to worship the hooded gods. The offerings include coins and snake effigies made of gold, silver and copper, grains of all kinds, pepper, tender coconuts, plantains, melons and sandalwood.