A drum roll is a series of repeated notes contained within a solid outline. These only appear on Expert drums though so you will need to play at a high level to unlock it naturally. By far the easiest drum roll in the game is at the end of Stop Me If You Think You’ve Heard This One Before. It is an easy song, and the drum roll is only five slow alternating yellow and blue notes. 25 or 6 to 4 also has an easy drum roll but it is at the end of a much harder song so No Fail might be required for that one.