Right after you insert the link, you’ll see a “ScreenTip” button. Click it. This is where you add a secret message.
Hover over your link later, and a tiny box pops up. Write “Danger: Do Not Click” or “Free Pizza Inside.” Your audience will giggle.
Pro tip: change the link’s color via the “Design” tab. Make it neon pink. Why? Because boring blue links are so 2010.