Oh, this is fabulous! You can't even stage one like this too much because you can't make a child laugh from deep within like that. You captured childhood at its finest!
This photo captures one of the most basic acts of play. The child's action not only represents playing in the autumn leaves, but is analogous with children playing in other substances such as snow, ball pens at MacDonald's or anything else they typically submerse themselves in and grab/throw up in the air using their hands. If I could picture any person having a great time playing (whatever that might be for them), they would have this child's facial expression. Great job.