The post discusses adding flying emoji reactions to a custom video call built on the Daily call object using React, CSS, and some Daily methods. It provides a step-by-step tutorial on how to achieve this, including creating a button that sends an emoji of choice flying on click, sending the emoji reaction to all other participants using the Daily sendAppMessage() method, rendering the emoji for both the local participant who sent it and the remote participants who receive it, and finally, using some CSS animations to make the emojis float around. The tutorial is part of a Next.js demo app that can be run locally by following specific instructions.