My Boxer Dog Has Started To Fall Over Loosing His Balance Also Trying To Lick His Backside And Walking Sidewards?

Your dog might be having peripheral vestibular disease that is causing problems of maintaining balance. Vestibular disease in dogs can be due to

   1. Head trauma
   2. Inner and middle ear infection
   3. Middle ear polyps
   4. Thiamine deficiency
   5. Some medicine that cause toxicity

Symptoms of Vestibular disease in dogs are

   1. Falling
   2. Circling
   3. Drunken walk
   4. In coordination
   5. Rolling
   6. Head tilt
   7. Eyes drift

So, take your dog to vet for accurate diagnosis and treatment because each cause is treated differently.