Harry got addicted to Bitter Apple spray....

....and loved being squirted with the water bottle (he thought it was a lazy way of having a drink...

) 
I think I read on here somewhere about using a mens unperfumed roll-on deodorant (or was I dreaming?! 

)...but it would take a heck of a lot to do all your walls.... 
It 
does stop with age and time, in the meantime - loads of chew toys, diversion, and exercise! 

 Good luck! Sally + Harry x