In this video, Kansas City Chiefs quarterback shows us how not to do an end zone celebration following a touchdown.

At the end of the first half, the Chiefs scored their first points of the game as Cassel connected with Dexter McCluster on a nine-yard touchdown pass.

After the throw, Cassel decided to celebrate the touchdown by some kind of leap into his teammates. It didn't go as he'd planned however, as he lost his balance and fell on his backside.

Oh well, it is only the pre-season.