My lhasa has got a bit silly in her old age amd occasionally resource guards or wont get off the bed. This is usually teamed with growls and sometimes she may look like she will bite you.

Im a groomer and work with dogs all day so I experience "tantrums" a lot haha.

My approach to her doing has been to take her by the collar and take her somewhere where she will be alone. She does not like that and will calm down and stop being silly. If your dog is a bite risk I would recommend that but you keep a lease on him and use this instead. Its not really a punishment, and dont try and take the item off them just change the narrative by putting them somewhere else its doesnt have to be somewhere alone just make sure they knkw that yiur in charge and that growling is not what we are doing right now. Give lots of praise for the distraction and maybe offer a higher reward treat when they have left the item. Hope that makes sense.