In the sixth episode of "Relax with Excel," the podcast introduces Excel's Flash Fill feature. Flash Fill automatically fills data based on patterns. The episode demonstrates this by entering names in an Excel file and using Flash Fill to format them as 'Last, First.' It explains step-by-step how to use Flash Fill both through the menu and with the keyboard shortcut Ctrl + E. This easy-to-follow guide is designed for learning, whether listeners are fully awake or drifting off to sleep.