Chris Brush from ChrisBrushDrums.com offers up a humorous look at drum fills, their acceptability in a typical drum session, and what they say about you as a player. There are "reliable" drum fills that are safe in any session context, "shady" drum fills that ride the fence depending on the song and producer, and "naughty" fills that should never be played for any typical session. Chris demonstrates and comments on each. Take it with a grain of salt.
