When I first got Sepp last year I taught him to "ring the bell" when he had to go out... I had a long strap w/little bells attached to my door knob, and he touched it w/his nose when he had to go potty, making it jingle.
So, that developed into me being summoned umpteen times a day to open the door to let him out... not just to go to the bathroom, but whenever he felt he wanted to go outside.
A few weeks ago I finally removed the bells, and he started touching the door knob itself... it's not noisy, so I can ignore it.
Today it's pouring out, so not much outside-time for the dogs.
About an hour ago I heard a weird noise... sounded like one of my clickers.
I went to check... and there was Sepp, at the front door, pushing his nose really hard against the clicker that hangs on the door knob by a wrist coil.
Of course, I opened the door, like the dutiful servant that I am. I'm going to try and get some video later, if I can.
Damned dog is too smart for his own good.