Help I have a nappy horse which needs some manners!

[Kokopelli]

His teeth and back are fine he doesn't nap at home at all and this is the first time he's done it at a show but heres what he did basically:

http://www.horseandhound.co.uk/forums/showthread.php?t=396128

Any advice welcome I'm really down about it so please don't be horrible!