Sprout has never told us in any way that he has to go, but over the years upon years of having him we just sort of 'know' when it's that time for him and let him out. He has a certain walk when he has to poo - similar to a full diaper-walk on a toddler. lol He's a clockwork dog - same times every day.
Bella is trained to potty pads and she doesn't tell us when she has to go - she just goes. However, she's definitely vocal about when she's already gone because she waits around for potty treats. She has now started adding new things she knows to her "after poop encore" such as sitting, laying down and "sitting pretty" for her potty treat.
