You need to re-assert yourself as pack leader and place yourself in the dominant position…….show that you are the boss and take the dog firmly by the collar and pull him off the sofa…..it is your sofa not his. he clearly thinks he is the boss of your house and you just need to remind him that he is not….body language and assertiveness are all that is required….electric shock treatment is only for extreme cases and as I said before should only be administered by experienced trainers. good luck
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Hire a dog trainer instead.
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At just 8 months old, he’s a junior dog and this is the equivalent of the canine terribles two. A hitherto quite well behaved dog can suddenly decide to test you to see if the boundaries set down as a puppy really are what you mean.

Get help from a canine behaviourist, a home visit might be a good idea initially, then if he’s not still going, take your dog to obedience classes to refresh and reinforce his training.

If the puppy was rather indulged, then it’s not fair to punish him by zapping him with a shock collar. Firm, fair and fun training, setting out the ground rules of what is acceptable behaviour and the whole family sticking to the rules.

Start with easy things like when you are going to fed him, ask him to sit first and wait 30 or so seconds before putting his dinner dish down. Make him sit before letting him out into the garden, before you open the door to take him out on a walk.

Put a house lead (thin lead) on his collar, so if you are having a problem getting him off the sofa, you can tug on the lead and avoid a confrontation. Until he learns his place in the pack, have a crate or his bed in the lounge and only let him sit on that. Allowing dogs onto a sofa ect is not a right. You need to be able to command your dog "off" and it will get down.

Good luck, and remember be as quick to praise for good behaviour as to censure bad behavior.
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Having never used such a device, I can’t offer you an informed opinion regarding the quality of the correction products from China.

I have to offer the opinion that the very fact that your dog is on the sofa in the first place is that your dog is in a position of power in your family that he should never have been allowed to assume in the first place!

His age suggests that it should be possible to put things straight, but I feel that you might be inexperienced with dogs and their training!

I have inherited a dog who was never socialised or given any boundarys. She is a beautiful, incredibly loyal dog, but she is also as tough as old boots and would not accept a position in our ‘pack’ which is appropriate! As I don’t have the time to put into correcting such ingrained behavioral problems, and frankly I lack the skills and experience to do so in a dog of her age (She is 4), I have had to resort to placing her with a professional trainer. Though he is a military dog trainer and a police dog trainer, it has taken him one and a half weeks of intensive work to even get her to recognise his authority!

This is the kind of problem you are setting yourselves up for if you don’t deal effectively with the situation at this, still fairly early stage!

I would suggest that you seek out a qualified professional to advise you as this aggression is worrying to be honest, but is more than likely correctable. But please, don’t let the grass grow under your feet. This is serious business!

Best wishes to you.
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