He is Aware That His Paws Don’t Belong on Screen
Because he used to constantly place his paws on the screen, this German Shepard was likely unaware of his size at one point and caused some harm. His parents made it clear that he was no longer permitted to do it for this reason, and he appears to do a pretty good job of abiding by the rule. He frequently crouchs in front of the door to ensure he gets the best look because of the no-paws policy.
This dog appears to go into full bunny mode when he peeks out the front door since he is well aware that his paws are not permitted anywhere close to the screen.