Vickie,
This sounds silly, but when you hear him going, speak up with the same
phrase every time, such as: "Gotta go pee?" Yes, I really do say that
in front of people. Hehe
It's a good idea to pipe up with your phase when another nearby horse
is relieving itself. My horse caught on rather quickly, although he
isn't all the way trained to it yet. We're working on it. I kinda wish
I'd started with a different phrase though!
Good Luck!, Nikki