These pics are about 3 yrs old, when the models were pups. Their looks have "matured" somewhat. Anyway, the dude on the right is theoretically the head of the household. Actually, he's always been a timid and sort of sad little dog, mostly undemonstrative. She is an outrageous flirt and perky and a glory-hound.
When they're both outside and they're ready to come inside, he has long been the master of standing on the hind legs and banging the door with his fists. There's a sheet of see through plastic protecting the screen, so it all makes a loud banging noise. Very effective and appropriate. He was doing that before she joined our pack, but she stands by behind him, since apparently she knows what the procedure is but does not allow herself to do it. But as soon as the door is opened for them, SHE swooshes past him, in front, to enter FIRST. When she's outside alone and needs to signal for entry, she just mews (like a cat) and beg-whines, does not "knock".
As for him, he apparently believes that this knocking thing only works at the front door. Whenever he is at the back and wants to come in, he stays about 5 feet back from the door, looking up through it when he hears somebody there. Both of them seem to prefer the front door 95% of the time.