If your dog is dominate and has the "alpha" position right now, you do not want to try to do this yourself. It could get nasty. Find a trainer that understands dog behavior, that will help you.
You do not have to be mean or tough to take back control. Small things tell the dog that you are boss. Don't let him bolt through doors before you. And no doggy doors, you control when he can go outside. Set a feeding time, don't leave food out all the time. Food comes from YOU. Make him sit or lay down before getting his meals or treats. Don't feed him off your plate. If you feel you MUST do this, then wait until you are done eating, then give him the treats.(leaders eat first) Do not allow the dog on the furniture. If this habit is already in place, then he should at least move when you want to sit.(dogs will naturally take the "best" place to sit, you make him move to a diffrent spot, you deserve the "best" spot, you are the leader) He should not be allowed on the bed, but again, if he already is allowed on the bed, then you get in bed, get comfortable, and THEN allow him on the bed. But you don't move for him. Do not step around or over him. If he is laying down and you have to walk there, he should move.
You definitly do NOT want to do a physical confrontation. Do not try to "roll" him, or hold his muzzle. Just slowly and steadiely start taking control. I rescue Rotts. This breed is very dominate, and I have had to go get a dog out of an owners bed, out of an owners car, and rescue a lady from her back yard. ALL three of these dogs were sweet and kind. They had just become the "leader" in there houses, and needed a little retraining. One went back home, one I kept, the other is now a therapy dog for a childrens hospital. Dominace does NOT mean that the dog is mean. Many people accidentally get the most dominate puppy by picking the "first one to run out and greet me". There was a reason he came first!! Again, get some help, in person, because no one can tell you exactly what your dog is doing by on-line methods. Basic obedience classes are very cheap, and will help more than you will believe!

