[pk's mom]

We've had our 7 month cocker spaniel for almost 3 months now. When he was first with us, he was too little to jump on the bed, couch or any other furniture. However, occasionally my husband or I would let him (meaning pick him up and set him with us) get in bed with us in the mornings after we'd let him out of his bed, but before we were ready to get out of bed and fully pay attention to him. It was perfectly fine for a while. But now he's teething and chewing just about everything he can get his little mouth on. Not to mention he's now big enough to jump on the bed all by himself and does whenever he thinks we're anywhere remotely near the bed.
I discovered the other day that he has chewed several holes in my bedspread. My husband and I decided right then that this habit of being on the bed needs to stop NOW. We admit that we fostered the environment for the habit to grow, however is there now a way to reverse that? Surely if he's still very much in his puppy months we can train him the other way. Right?
Any ideas? Do you do this by forceful training (No! Get down!), or is positive reinforcement more effective?