Sesame ball has been a common snack in China since Tang dynasty, which made by sticky rice, red bean paste and sesame. People in Guangdong normally make seasame ball before Spring Festival. In Guangdong custom, the bigger sesame ball you make, the more fortune you will have in the next year.
There is a beautiful story behind the sesame ball - Nuwa, the goddess mending the sky. It is said that Nuwa, the goddess in Chinese mythology, mended the sky, while produced animals and human being in the first seven days, which made her felt so tire that she fell asleep in the 19th days. The construction of mending the sky had not finished yet, but people did not want to wake Nuwa up. Therefore, they cooked the sesame ball and put them on the roof with red string for making up the sky temporarily.