Once the band starts, everybody starts swaying from one side of the street to the other, especially those who drop in and follow the ones who have been to the funeral.
Once the band starts, everybody starts swaying from one side of the street to the other, especially those who drop in and follow the ones who have been to the funeral. These people are known as 'the second line', and the may be anyone passing along the street who wants to hear the music. The spirit hits them and they follow along to see what's happening.