Okay kiddo, imagine you have a little cut on your hand, and your body needs to fix it so you don't get hurt anymore. When this happens, your blood turns into a jelly-like substance called a clot, which helps stop the bleeding and forms a protective barrier over the wound.
Inside your blood, there are tiny little things called platelets, which help make the clot happen. They stick together and form a plug to stop the bleeding.
Now, some smart doctors found out that if they take some more of your blood and spin it around really fast, they can separate out the parts that make the clot happen, including the platelets. Then, they take out the best parts of those platelets and put them back into your body where there was a wound.
This special mixture of the best parts of your platelets is called platelet rich fibrin. Because it has more of the important parts that make the clot happen, it can help your body heal faster and better.
So, to sum it up, platelet rich fibrin is a special mixture of the best parts of your platelets that doctors can use to help your body heal faster after you get hurt.