@little_t Just a further note. What you want to avoid is turning "I don't want to and you can't make me" into a fear reaction because you come down too hard on him. You need to be firm and matter of fact without doing something he perceives as a threat, so your goal is to enforce your rules but not to punish for the disobedience. Also, you need to be consistent. If the couch is off limits it is off limits. Be clear about what you allow and what you don't, and make sure everyone in the household is on the same page.
OTOH, if he is normally allowed the couch and for whatever reason you want to move him from his comfortable spot, best to finesse it rather than turn it into a confrontation, but if it becomes one you must follow through. The fastest way to create a biting dog is to show him he can get his way through a growl or threatening to bite. BTW, this is how he would treat another pup, not how he would act toward his mother. She would not put up with it!
Just to add, I am with Zande on the harness issue. Personally I like a martingale collar, but if the issue is pulling then you need to work on loose leash walking. Basically you don't proceed when the leash is tight. He will learn.