The divine bull Nandi was born in this temple and became the mount of lord Shiva.The divine wedding of Nandi and Suyasayambikai was held at Thirumazhapadi Vaidyanathaswamy temple in Ariyalur district of Tamil Nadu. This is celebrated as Saptha Stanam festival which includes seven Shiva temples of the region.
The sapthasthanam festival is conducted at Tiruvaiyaru during April every year. As per Hindu legend, it is the wedding festival of Nandikeswara, the sacred bull of Shiva on the Punarpoosa star during the Tamil month of Panguni.
The festival deity of Aiyarappar temple of Thiruvaiyaru is carried in a decorated glass palanquin along with the images of Nandikeswara and Suyasayambikai to the temples in Thirupazhanam, Thiruchottruthurai, Thiruvedhikudi, Thirukandiyur and Thirupoonthurthi. Each of the festival deities of the respective temples mounted in glass palanquins accompany Aiyarppar on the way to the final destiny, Thillaistanam.
There is a grand display of fireworks in Cauvery riverbed outside Thillaistanam temple. The seven palanquins are carried to Aiyarappar temple in Thiruvaiyyaru. Hundreds of people witness the convergence of seven glass palanquins carrying principal deities of respective temples from seven places at Tiruvaiyaru. The devotees perform Poochorithal(flower festival) in which a doll offers flowers to the principal deities in the palanquins. After the Poochorithal, the palanquins leave for their respective temples
The temple priests perform the puja (rituals) during festivals and on a daily basis. Like other Shiva temples of Tamil Nadu, the priests belong to the Shaiva community, a Brahmin sub-caste. The temple rituals are performed four times a day; Ushathkalam at 6:30 a.m., Kalasanthi at 8:00 a.m., Uchikalam at 12:00 a.m., Sayarakshai at 5:00 p.m., and Ardha Jamam at 8:00 p.m.
Each ritual comprises four steps: abhisheka (sacred bath), alangaram (decoration), naivethanam (food offering) and deepa aradanai (waving of lamps) for both Odhavaneswarar and Annapoorani. The worship is held amidst music with nagaswaram (pipe instrument) and tavil (percussion instrument), religious instructions in the Vedas (sacred texts) read by priests and prostration by worshipers in front of the temple mast.
There are weekly rituals like somavaram (Monday) and sukravaram (Friday), fortnightly rituals like pradosham and monthly festivals like amavasai (new moon day), kiruthigai, pournami (full moon day) and sathurthi. Mahashivaratri during February - March is the major festivals celebrated in the temple.