I would always have a dog vet checked if there is a sudden change in temperament and also if there are issues of ‘aggression’. The two most common triggers in dogs for aggression are pain and fear. You do need to know that there is no underlying health issue before trying to resolve this.
With young dogs / puppies over-tiredness can also play a significant part in them reacting with unwanted behaviours when they are touched, moved or even during play. You do have to make sure that Lily is getting plenty of relaxation and rest time between any exercise or training. The fact that you say she is worse late at night sounds as though being over-tired or over-stimulated may be part of the problem.
I definitely would not use any physical punishment or restraint as a training technique. Positive gentle training techniques are proven to be the best and using force can lead to a worse situation. You need to encourage her to get down or be lifted down from a sofa or lap and reward her for doing so. Train this regularly every day as it needs to become instinctive for Lily to be willing to respond to being asked to get off a lap or sofa, it isn’t something that you can just do when the situation arises. Training a puppy can be fun but it does need patience and repetition as often as possible to get it ‘hard wired’ in the puppy what you want them to do but always reward success or moving towards success and don’t use any force to try and speed things up. It will take time but the younger the dog the quicker they learn
From your post, Lily sounds a lovely dog and you mustn’t think you are a bad owner. Everyone even those most experienced with dogs have days or individual dogs who are a challenge. I think that Lily may be getting over-tired and / or over-excited and she needs both plenty of rest and maybe more mental stimulation such as puzzle toys which can occupy her when you have visitors. Check out the Nina Ottosson games for dogs which are excellent.
Being prepared for possible challenging situations can also help in some cases. Having a blanket there for someone to put on their lap before Lily jumps up and a toy or even some treats to thrown down on the floor for her to encourage her to jump down in an unexpected situation where you need her to get down but won’t need to physically move her. Some dogs do temperamentally dislike being picked up, handled or physically moved and, although it is important to try and train them to accept this as it can be absolutely necessary at times, it is well to be aware if you do have a dog that doesn’t like a lot of handling.
Lily will also be entering adolescence and as her hormones surge it can lead to some behaviour changes and a reluctance to respond to training but this is a phase and she will come through this as she matures but is possibly an additional factor to bear in mind. Patience is vital here
These are just some suggestions but a vet check is a good idea when any untypical behaviours appear in a dog or puppy to put your mind at rest that this is not a health related issue.
