I don't use the word "stay" until my stays have duration, distance, and distraction. Sit means sit, down means down. If I say sit and my dog sits I can withhold the rewards for a few seconds. When I give the reward, as long as the dog stays put, I can quickly reward again. It doesn't take long for the dog to realize that until they get the "Ok" it's beneficial to stay in the same position.
When I get past the association part of teaching the command I don't use the clicker. If my dog can sit on the command he doesn't need to be clicked. At that point, if I'm working with a high distraction level, I usually switch to the word "yes" followed by the reward. To me that cues the dog that we are no longer shaping the behavior, but he/she still has the oppoerunity to be rewarded for it.