My twins were 3 when Otto was a pup. There's nothing really rude about it, the dog just finds you more entertaining. Teach your son to throw a ball.
I agree you do not want to leave a 3 year old child outside alone with a young GSD. Especially one who's trying to get his attention. Not saying your son will do anything *wrong* but I have 2 boys. Little boys don't always think through the long game...
Venus of Crooked Creek 1/26/13
Otto von Hena-C 05/23/08
Morgan Donnermond 08/04/01 to 9/28/12 Long Live the Queen!
I have duct tape and I am not afraid to use it.