How can I teach a grown dog to sit?

Hmm, I'll try doing what you both suggested. I think I'll have to start off by teaching him how to behave, yes, because when I walk him, he's like a powerful boat pushing a water boarding board(me). Apparently I'll have to search for a good treat to use though, since I cannot use his favorite toy because he'd just go and take it from my hand, and food, well, he isn't the kind of dog that starves for food. As I said in some other thread, you can even drop a stack of meat that he wont care about it. He'll just stay sat, looking at it while we bend down picking it from the ground. I'll give it a try and update this thread afterwards with the result.

Thanks for the advices.