What happens when you try to ride a great dane?

We stopped by Jenny and Michael's house this evening. They have a great dane, Rudder. In case you didn't know, the "great" means HUUUUGE. it looks like a human being. anyways, i thought it would be a good idea to try and ride him. Hilarity ensued.

http://www.youtube.com/watch?v=y_V0cXTI5os