Puppy doesn't signal to go out
My 5 month old Westie puppy is toilet trained but he doesn't bark or signal in any way when he needs to go out to wee or poo. I have to take him outside every 2 hours during the day to avoid any accidental mess indoors. However he manages to control his bladder at night for upto 6 hours. Please could you tell me how I can teach him to bark at the backdoor or signal otherwise. I don't think its possible to continue with such frequent trips outside everyday.
I would really appreciate any suggestions.