When we first start out clicker training, we tend to get very excited about the fact that we can teach the dog a new behavior in just a few clicks. Suddenly we have a dog that sits, does a belly flop down, a spin, a paw wave, and six other things-but all at once. You're hoping for a sit/stay, and the dog is running through his entire repertoire trying to find something you'll click.
Cues and Cueing
Train two behaviors at once? Teach two cues simultaneously? How? Why? Teaching certain cues in pairs can speed up the learning process, as well as teaching a dog a concept that it can apply to new learning.
If the learning is sufficiently shaped and reinforced to the best it can be, and reliability is achieved at this level; and if, then, this standard is attached to a new "performance cue", then there is no reason for the dog to give a reduced quality or reliability in show circumstances unless the stress level has gone beyond the dog's self management. Even then asking the dog for a strong, favourite behavior can reduce the stress significantly.
"Tell me this," said the Old Falconer, rocking back on his heels a little. "I want my bird to come back to me when she's too far away; but I want her to come back AND to stay up in the air. If I give her your click signal for coming back, she's got to come down to me to get her reward, right? So how can I do that and still get her to stay overhead?" And he glared at me with "Gotcha!" in his eyes.