Okay, kiddo, let's break it down step by step.
First, have you ever heard of a book with words and pictures in it called pulp fiction? It's like a storybook, but usually with exciting or suspenseful stories.
Now imagine people who really like these kinds of books. Sometimes they get together to talk about them and admire the cover art (that's the picture on the front of the book).
But here's the twist: these people also like to be outside, in nature! And they also like to be comfortable, so they don't wear shirts. That means they're "topless."
And another twist: there are both boys and girls in this group, so they're "co-ed."
So, all together, this is a group of people who like to read and talk about pulp fiction stories, while being outside in nature and not wearing shirts (if they want to). They call themselves the "Outdoor Co-ed Topless Pulp Fiction Appreciation Society."
Does that make sense, little one?