Shaun Preece, host of the AMI original podcast "Shaun of the Shed," explains in a quick episode how to customize gestures on a smartphone to make it more efficient for blind or partially sighted users. He highlights that gestures are used as a basic navigation tool for blind users, and there are many gestures that don't have any functions assigned to them that can be customized to improve the smartphone's usability. Shaun demonstrates how to customize gestures on an iPhone and an Android device, providing a step-by-step guide to change the gesture function. He emphasizes the importance of being careful while changing gestures, as it can completely change how the smartphone operates.