Briefly, this means that you becomes the point of view. Examples:
- Third person: John dropped the live goldfish into his mouth. He flinched as his Adam's apple bobbed up then dropped down, and then he went very pale.
- First person: The goldfish never stopped twitching. I dropped it in my mouth, and I could feel its tail flailing against my tongue, my gums, the back of my throat. I swallowed hard and felt the thing wriggle all the way into my stomach, swimming for dear life against the waves of peristalsis.
- Second person: Your thumb and forefinger spread the tiniest bit, and the live goldfish drops into your mouth. You force your lips shut and try to ignore the creature's tail fin flagellating your gums. You think one thought over and over again as you force your reluctant muscles to swallow: It's just like sushi. It's just like sushi.
Ulterior motiveWhen second-person point of view is mentioned (if it's mentioned at all) in books about novel writing, the advice usually looks like this: Don't use it. It's perfect for assembly instructions, choose-your-own-adventure novels, and books about novel writing, but it's rarely used in serious fictional storytelling. Rarer still is its successful use in fiction.
Nonetheless, you have second-person POV in your writing toolbox if you need it. So you ought to have some idea of how to use it. So try it, take a few swings with it, and then put it back in your toolbox.