You will think I am mean...
I used to put lemon juice in the squirt bottle with my German Shepherd (God rest his soul!). He was a very stubborn "alpha" male type of dog and I tried everything to get him to listen. Lemon juice worked--very diluted, but worked.
He got squirted once in the eyes and he learned to fear that stupid squirt bottle. in fact, I could put it in a doorway and he wouldn't enter the room.
Rose Hall