The origin of the festival, some believe, lies in the Shushunia hills of Bankura. Other folklorists  connect the festival to the worship of an agricultural folk goddess named Toshali Debi (also known as Toshla or Tusu elsewhere in West Bengal) since ancient times as part of the Tush-Tushali ritual (broto). This is a fertility ritual of the soil performed throughout the period of the festival, in honour of the goddess. Yet other scholars opine that traditionally the festival was celebrated only by the Kurmis (Kudumi/Kudmi), a former tribal community, concentrated in and around the Chhota Nagpur region and which was, over time, adopted by other tribal communities such as the Bhumij, Mundas and Oraons.  The festival has spread along with the migration of these people. Thus, parts of  Hooghly, Bardhaman, Birbhum and also the  Sundarban areas of South 24 Parganas witness the celebration of this festival these days. North Bengal and Assam too are home to these celebrations only because of the forced migration of  tribals to these regions during the British Raj.

What has been established is that Tusu was originally a tribal festival that was later also adopted by other communities who lived in close proximity. Therefore, the goddess today is worshipped by both tribal and Hindu communities.  It is a people’s festival related to fertility and it is celebrated chiefly by the Hinduized Kurmi Mahato caste, who have maintained their traditional rituals. The Tusu festival remains the woman`s domain and the rituals observed during the festival continue to oppose the larger temple-based diktats, with their traditions of Sanskrit texts and commentary and specialized priestly class. However, as a result of acculturation, traditions have merged and the lines between Hindu and tribal have blurred.  

Tusu is welcomed with song by the women every day of this festival - during periods of rest and also during various household chores and other work. On the eve of Makar Sankranti, the women fast and sing all night. The older Tusu songs were fundamentally songs of fertility - both a pleading to the earth for a plentiful harvest as well as an embodiment of erotic imagery. Its melody was plaintive and there was no instrumental accompaniment. Devotion to Tusu is a part of the larger worship of natural forces including hills, forests and river gods. The songs (‘jagaran’ songs) are believed to awaken Tusu, the virgin unplanted earth and the goddess of fertility. Others say that these songs are sung to seek her blessings so that the next harvest is also good. However, the overarching traditional belief is that Tusu is a mother, a daughter, a friend, a beloved  or protector to whom the women can pour their hearts out to. The older songs thus dealt with welcoming Tusu, their prayers for happiness and prosperity, their daily lives,  their joys and longings, their sorrows and struggles  (including protests against co-wives, in-laws or husbands) and so on. In modern times however, the form is also used for completely non ritualistic reasons - as political songs, as protests against corruption or immorality. as commercial love songs and even as material for local school competitions. And these days, the singing usually takes place with instrumental accompaniment. 

One popular story says that the Tusu festival originated in the thirteenth or fourteenth century in commemoration of a brave woman who defended the granary and fields against invaders. A current Tusu song uses this imagery:

Tusu has picked up a sickle in her hands

And she is going to harvest that rice

Which is grown with blood.

Landholders will come rushing up

[But] Tusu has courageously made up her mind

She holds the sickle with a firm grip.

Sometimes, a song may combine roles:

Tusu is our goddess, Tusu is our protector

But she is also our daughter and we protect her

This year we had a drought

So our worship of Tusu is not luxurious

But next year Tusu, by your grace

Our prayers will be answered

And our crops will be lush

Then we can worship you with joy and happiness and feasting

In some parts of West Bengal like Bankura all the ingredients for the worship are placed in a round terracotta pot surrounded by tiny lamps. The main ingredient is tush or rice husks on which are placed five, seven or nine cow-dung balls, some rice, flowers of radish and mustard (which grow during the season), marigolds, and the crown flower (akanda in Bengali) together with vermillion and other auspicious objects. This earthen pot is called Tusu-khala or Alo-khala because lamps (alo means light) are placed around its rim. It is placed in the Kulungi or a niche in the wall and in the evening women sit around it and sing songs of Tusu. 

In Purulia and some parts of Bihar and Jharkhand, the celebrations centre around the Chaudal. The chaudal (from chatur  dola or four sided palanquin) is a rectangular structure made of brightly coloured paper and bamboo, something like box-kites and is up to six feet tall. The worship in this belt is aniconic - there are no idols (though lately, images have been noticed). The protectress of seeds, Chauri, is worshipped on the first of the three final days. Chauri is associated with the goddess Chandi (another name for Kali) and also with Rohini, the woman who, it is believed, discovered the first seed. On the first day of the festival, all rice on the farm is to be brought to the family house, and on the second day, small bundles of grain are made and put into the granary for the next year’s crops. On this day, the chaudal is bought and two cow dung balls placed inside, representing the union of male and female qualities in the form of the  sacred couple ‘Tusa’, the male, and ‘Tusi’, the female. Together they form ‘Tusu’. Tusi is topped with rice husks. 

The dung balls within the chaudal have been worshipped the whole month in home altars in wall niches decorated with "alpona". The women have sung in front of the altar since the beginning of the festival. On the eve of Makar Sankranti is the awakening of Tusu. Bonfires are lit from discarded rice husks and young girls sing and dance around them all night. The next day, Tusu devotees gather in the morning for ritual baths in the river or ponds. Then  dressed in all their finery, the women carry the colourful, gaily decorated chaudals on their heads as they parade through the village and fields singing Tusu songs. They are accompanied by musical instruments, usually drums, played by the men.  The chaudal is finally immersed in the rivers or ponds. In Purulia, this is mainly along the banks of the Subarnarekha or the Kangsaboti or the Silai. Songs are sung bidding the goddess farewell and inviting her to return next year.

In other areas of West Bengal, where the Hindu influence is stronger, Tusu is often represented by an image of goddess of Lakshmi. This is true of Tusu celebrations in the Sunderbans, for example. The southern areas including Medinipur and Bankura do not have chaudals, though they do tend to have idols. Here, Tusu is a tiny doll.  Her crown and ornaments are  made of tin-foil and her sari of blue or red paper. On the first day, women wash clothes, catch fish, make rice powder, and collect funds to buy dolls made by the local potter. These are carried on brass plates while the women sing songs about village life (especially about fighting between co-wives, family frustrations, harsh moneylenders and problems with land ownership). On the second day, the dolls are again carried around the village, and sometimes a marriage is negotiated and celebrated between two dolls, complete with a wedding party and drummers. On the third day, the image is taken for a last look at the village, then carried in procession to be immersed. New Tusu songs are composed every year. 

If there is more than one Tusu being worshipped in a village, it is also customary for  the groups to garland each other`s Tusu. During the month long festivities, mock competitions often take place between various Tusu groups in the village. There is also flirtatious exchange between groups of boys and girls in the  form of erotic imagery in the songs that are sung. But at the time of the immersion, women cry and mourn and beg Tusu not to leave them. 

Originally, the language of the festival songs was neither Bengali nor Hindi but tribal languages such as Kurmali (which has no script) and handed down through oral tradition. The songs are oral histories of the tribes. In recent years some songs have been written down in Bengali script.

One interesting aspect of the Tusu festival is that it is a tradition that has encouraged the creativity of young women, for if their songs are worthy they will be remembered and sung by the older women of the village. It thus can be viewed as a strategy for preserving oral history.