It seems to call for you with an "!" over its head every three hours or so just to say hello. When you press the "A" button, it walks up close to say hi and then the attention icon turns off. I disciplined mine once when he did this as a teenager, but I didn't take note of the training bars beforehand to see if it actually did anything. He still calls every few hours with a "!" as an adult, and just walks close to the screen when I press "A".
As far as I can tell, catching a young Tama-Go using the toilet is the best way to fill training bars. I still have no idea when to use a time out.
The only time I know for sure why he calls with a "!" is at 6:30, when he gets into the bathtub when I press "A."
