Training mom

When I tell our dogs to do something, like "out" or "go away" or "leave it" and they look at me like I'm speaking a foreign language, I add a clap to the command to let them know that I mean it.
Today Joshua wanted to get up on the bed to watch a show (which I wasn't allowing because he had already watched Kung Fu Panda today) he kept saying "upf" "upf" (he adds a fricative to all his plosives) and then he looked at me and said "upf!" and then clapped his hands at me.