David Vallejo presents a tool called Analytics Debugger that allows users to easily debug Google Analytics implementations on non-desktop devices. The tool works by adding a custom task to the Google Analytics setup, logging into the Analytics Debugger website, starting a debugging session, and opening the preview link on a mobile device. It also allows sharing debugging sessions in real time so multiple people can view hits. The goal is to provide a hassle-free way to test Analytics tags on mobile.