hi doreamon,
The one I used on cookie for furniture is Bio-Groom's bitter spray. I used Four-Paws on her. Besides the spray, do you punish wye wye in any way when he chews what you dowan him to chew? I used to lock cookie up in her cage (it's a rather big one) when she does something wrong. It's called the 'sin bin' method. It's like grounding your child by sending him to his room and not allowing him to come out and play. The place where you lock him up must be a very boring place for a dog, i.e., no toys, no papers, nothing to chew, no food and no water. Lock him up for about 10min first, speak to him really loudly like you're really really upset with him right before you put him in the cage. Dun even look at him when he's locked up. Deprive him of EVERYTHING, including your companionship. After he's let out, if he does the deed again, sound very upset again and lock him up, this time double the time. But when you see that he doesn't chew the furniture or whatever you're trying to train him to do/ not to do, praise him profusely like you win 4D like that. Haha..
Or give him a treat. Most puppies learn well this way. After they grow older it becomes harder to train with any method.
I just went back to read your previous postings about wye wye, you said that he eats his poo poo at times? Does he still do it? All his actions are behavioral problems which need you to be really firm with your leadership role. Basically wye wye needs to know that you and your hubby are the boss and he is NOT. Never let him win when you play any games with him, even if it's just fetching, make sure you are the last person to get the ball and keep it. Aiya, I said a lot hor, I'm sure you already know these lah.
Dun mind me hor, I can be very long-winded. 
The one I used on cookie for furniture is Bio-Groom's bitter spray. I used Four-Paws on her. Besides the spray, do you punish wye wye in any way when he chews what you dowan him to chew? I used to lock cookie up in her cage (it's a rather big one) when she does something wrong. It's called the 'sin bin' method. It's like grounding your child by sending him to his room and not allowing him to come out and play. The place where you lock him up must be a very boring place for a dog, i.e., no toys, no papers, nothing to chew, no food and no water. Lock him up for about 10min first, speak to him really loudly like you're really really upset with him right before you put him in the cage. Dun even look at him when he's locked up. Deprive him of EVERYTHING, including your companionship. After he's let out, if he does the deed again, sound very upset again and lock him up, this time double the time. But when you see that he doesn't chew the furniture or whatever you're trying to train him to do/ not to do, praise him profusely like you win 4D like that. Haha..
I just went back to read your previous postings about wye wye, you said that he eats his poo poo at times? Does he still do it? All his actions are behavioral problems which need you to be really firm with your leadership role. Basically wye wye needs to know that you and your hubby are the boss and he is NOT. Never let him win when you play any games with him, even if it's just fetching, make sure you are the last person to get the ball and keep it. Aiya, I said a lot hor, I'm sure you already know these lah.