The ascetic, was always focused about his meditation and had stayed away from worldly affairs. During the time of the churning of the ocean of the universe, the samudra manthan poison came out of the sea which threatened the sustenance of life on all the planets that bared life forms. In order to save living beings, Shiva drank all the poison. In return, Shiva’s throat turned blue and gave him a burning sensation that disturbed him in his meditation.
Shiva told Nandi to sit in front of him and blow air so that he could meditate with peace and concentrate. Nandi, the ardent follower of Shiva, accepted his master’s request and kept on blowing air towards him facing opposite to each other. In this manner, Shiva meditated with the help of Nandi.
It is also said that while praying to Shiva on a visit to temple, we should not go in between Nandi and Shivling, as it distracts Shiva from his meditation and Nandi can’t help him. If you have a wish to share then you should speak in the ears of Nandi, and he will convey all the wishes of the followers later when Shiva is not meditating. This shows the bond between the two friends: Shiva and Nandi.