Lydia discusses the use of easy sand or hot mud for pre filling when working with drywall. She explains the different sizes the product comes in and the importance of keeping it dry to prevent premature setting. Lydia also provides tips on mixing the product, controlling consistency, and cleaning up afterwards. She emphasizes the need for a skim coat of ready mix compound before painting over the hot mud to avoid issues with paint adhesion. Overall, she highlights the versatility and strength of easy sand for various drywall repairs, including plaster repair and filling holes and cracks.