It’s just very likely that there’s something wrong with him internally, much like how us humans can get a flare-up in an organ or feel a sharp internal pain.
This behavior is normally caused by some form of anxious response for your canine companion and this is their way of dealing with the stress.
This can be due to a variety of reasons depending on his upbringing, but it’s usually tied in the way you approach him.
It could be that he has gotten himself injured though a splinter of some kind, some unexpected impact or a cut that may have occurred in a more vulnerable area.
The reason why is either their unusual nature, or the loud noise that they produce which scares the dogs. It could also be newcomers to the household.
It means that something has irritated his anus, or anal sac to be more precise and he’s trying to scratch it. The usual culprits are allergies, a poor diet, accidental injury or even worms.
If you’ve moved recently, the new environment may still be unknown to him and he still may be adjusting which is causing these outbursts. It could be fear and this is his defensive mechanism.
Various internal issues, be it some form of illness or disease, other underlying health issues or potential parasitic infection may cause your dog to feel this way
The answer to the problem is usually tied to his gut in this case, namely some form of parasite or simply a severely upset stomach.
Dogs try to eject build-up stress by chewing on stuff, and, if they haven’t been trained properly, they tend to develop more destructive tendencies.
The most common culprits are, once again, tied to potential health problems, be it low electrolyte count or a heavy case of diarrhea.
The cause for this may again be a mix of fear, stress and anxiety, especially separation anxiety.
For adult dogs the cause is usually some form of illness or underlying health issue. It could also be the ultimate culprits - stress and anxiety.