Disgusting Dave and the Farting Dog

Meet Dave. He's disgusting - everyone says so. Even his mum is fed up with him examining his nose pickings. So now Dave's got a challenge: if he can avoid doing anything disgusting for a week, he gets a ?20 reward. He thinks he can do it. At least, until his arch-enemy, Banger Bates, lands him with Fred, the farting dog.