Or maybe

Don’t give in to him easily. Does he want something to eat or drink? First, make him sit. Then, let him work for it.

he could just do a trick or two for it. The idea is that aggression breeds aggression. If he is aggressive with you, he needs

to learn to accept it from you too. This doesn’t mean you punish him as that will only worsen the problem.

http://dogtrainingmastery.com/Dog_Training/dog-toilet-training.htm
http://top-ideas-online.com/Free_Dog_Training/potty-training-your-puppy.htm