1. To assert dominance. Whether it's jumping on people or jumping on furniture, both instances illustrate a dog that wants to raise his station in life. By jumping on you or jumping on the couch, he's saying that he's the pack leader--something that you DON'T want to happen, as a dominant dog is much more difficult to train (and can become quite aggressive). In either case, you'll definitely want to institute the proper alpha dog training techniques, if you haven't already.
If a dog is stressed or afraid, their demeanor and typical behaviors will change. If you see this in your dog (or really any dog you know) you should step back and check on your dog. Are they hurt? Did a new dog come around they don’t know? Has the weather changed? Is it hot outside? When was the last time they had a chance to go outside to pee or poop?
Make sure other family members and visitors understand this command, as well. It is crucial that your dog understand that all family and visitors are above his rank in the pack. Otherwise, he will lash out and try to assert himself on everyone. While using the Off command may not be appreciated by most visitors, but it is more important that a dog has a good greeting manner with all people. A little effort on everyone's side makes your dog disciplined and docile.
With a tie-down, you simply attach your dragline to a fixed object like a fence, stair rail or another immovable object like an eye-bolt in the wall. This exercise uses the same principles as teaching the “wait” command, only instead of closing a door or gate, the pup is confined by the leash. That keeps you safe from mouthing and claws and prevents the pup from jumping up and grabbing. Practice puppy sits and downs while you stay out of range. Only reward the puppy with contact from you when he stays calm with all four feet on the floor.
To a dog, space and balance are very important. If you take a step backwards or lean out of a jumping dog’s way, it will continue to jump. To a dog, it is overtaking your space, which only pack leaders are allowed to do. When a dog jumps, step into the dog. Picture a sphere around you and are not going to allow anyone or anything to come into your space. When the dog jumps, step into it sideways with your body, shoulder towards the dog. Don't face the dog head-on (you may not have time to turn so don’t worry about it if this is the case). You are not trying to knock the dog down, although this may happen. Don’t be alarmed if you do knock the dog over. Although you don’t want to abuse the dog by knocking it around, this may actually go a long way toward breaking it of the jumping habit as it will create a negative experience. Dogs are incredibly physical creatures and can withstand a lot of physicality without any harm. The odds of inflicting any serious injury are miniscule. You are simply calmly filling up your space with your body, and in return, setting the dog off-balance, which is an uncomfortable feeling for a dog. Lean slightly forward, not backward. Never lean backward, as you will be giving the dog that space. Casually and calmly, keep filling your space, not allowing room for the dog to come in. Remember, your goal is not to knock the dog down, it's just to retain your space.
Why do dogs jump up? A plausible explanation arises from their ways of communicating with each other. A puppy greeting an adult dog often licks the adult’s muzzle -- a polite, deferential behavior. Dogs, of course, descend from wolves, among whom muzzle-licking is how pups get the grownups to regurgitate food for them. Domestic dogs rarely nourish puppies this way, but muzzle-licking has survived, maybe because deferential behaviors are handy for a social animal. Think of humans saying “No, after you.” Muzzle-licking is also an appeasement behavior -- something you trot out to de-escalate a fight. A human might lift up his hands, palms toward the person he’s arguing with.