Samuel's going to illustrate how to have fun in a wagon.
First you get in. Make sure you have your milk. Oh, and you'll have to whine for someone to open the wagon door for you first.
Drop your milk in your excitement to sit on the wagon seat, while looking pretty pleased with yourself.
Reeeeeeaaaach to close the door.
Look pretty pleased to have accomplished the close-the-door feat.
Grab your forgotten milk and place in proper cup holder.
Exit the wagon, careful not to fall on your face.
That's how it's done folks. Hope you took notes.