Generally, Nag Panchami comes two days after Hariyali Teej. Though there are several variations to observing this vrat, most commonly, women offer their worship to Nag devta on this day. The main part of the puja is offering milk to serpents on this day. The main prayers on this day are for the welfare of the brothers of the women. In general, this puja is said to confer prosperity and welfare to all in the family.
In the south India, there is yet another version of this vrat called as Nag Chaturthi. Chaturti is the fourth day of Shuklapaksha falling one day before the panchami.
Some of those who customarily observe Nag Panchami observe fasting on Nag Chaturthi to conclude it with the puja the next day. However, in most parts of South India, Nag Chaturti vrat is observed with elaborate ritualistic puja for snake gods. This version of Nag Chaturthi comes after Diwali celebrations. The other version of this vrat include Nag Panchami in Gujrat observed during Krishnapaksha Panchami (fifth day of the dark half of lunar month) on Shravan month.
Before the beginning of the puja on the Nag Panchami day, reciting this mantra as many times as possible is considered highly beneficial and will set the right phase for the performance of this vrat.
Nag Panchami Mantra before beginning the Puja -
Anantham Vasukim Sesham Padmanabham Cha Kambalam
Shankapalam Dhartharashtram Thakshakam Kaliyam Thatha
Ethani Nava Namani Naganaam Cha Mahatmanam
Sayamkale Pathennithyam Pratahkale Viseshata
Thasmai Vishabhyam Naasthi Sarvatra Vijayee Bhavet
Meaning of Nag Panchami Mantra : In this mantra, the nine important snakes that appear in the purana stories are listed out and the snake is heralded as the reclining bed of Lord Mahavishnu (Padmanabha). It also goes on to say that chanting this mantra in the mornings and evenings regularly shall help avert harms from all forms of poisonings both internal and external and that the chanters will get success in every walk of their life.
Typically, the puja is performed either in Nag temple or at home. During the puja, sankalpam is done for vrat and puja. The main part of the vrat is offering a holy bath to the Nag devta idol. Milk is the main material used for this holy bath. Sandal paste, turmeric and vermilion are applied on the idol. Offerings are done and camphor is waved in front of the idol.
At the end of the puja, the performers chant the following.
Nag Gayatri Mantra
Om Nagkulaya Vidmahe Vishadantaya Dheemahi Tanno Sarpa Prachodayat
during the conclusion, Nag Panchami Vrat story is read and prasad is distributed to all those who are assembled.