Bhai dooj is a hindu festival, a ritual observed by Indian siblings, specially by girls for the well being of their brothers. This ritual is celebrated among Indians living in any part of the world. Bhai dooj is observed on the second day of Diwali, known by different names in different parts of the country,like Bhai Bij, Bhaubeej or Bhav Bij amongst the Marathi speaking communities in the states of Maharashtra and Goa. It is also known as Bhai-phota or Bhai phonta among Bengalis. The name 'Dooj' means the second day after the new moon, the day of the festival, and 'Bhai' means brother.
On the auspicious day of Bhaiya-Dooj, brothers and sisters get up early in the morning,take bath,wear new clothes and get ready for the day. Brothers visit the places of their sisters and on the arrival of their brothers, the sisters perform 'aarti' of their brothers and apply a the 'Tilak' or 'Teeka' on their forehead. The sisters they sweeten the mouth of their brothers, with mouth-watering eatables, such as ladoo,kheer,puri,kachori and other sweets. Thereafter,the brothers and sisters exchange gifts with each other. On the auspicious day of 'Yam-Dwitiya', the people of 'Kayastha' community of Hindus celebrate the holy function of worshipping Lord Chitragupta, the God who maintains the records of life and death of the living beings. The 'Kayastha' community also worship the pen, paper and ink on this day, in the honor of Lord Chitragupta.
According to one legend, on this day, Lord Krishna, after slaying the demon Narakasura went to his sister Subhadra who welcomed him with lamp,flowers and sweets, and put the holy protective 'Tilak' on her brother's forehead.
It was believed that on the day of 'Yama Dwiteeya',Yamaraj the Lord of Death and the Custodian of Hell, visited his sister Yami, who put the auspicious 'Tilak' on his forehead and praying for his well being. So it's held that anyone who receives a tilak from his sister on this day would never be hurled into hell.