Clicker training works great, but there is a small problem -- the clicker itself!
You see, if you have a clicker in one hand, it's more difficult to cue a dog with hand signals. And hand signals work.
In fact, hand signals work better than voice signals to initiate a behavior, as dogs are more wired for sight than sound.
Tie a spoken word or two with one or two hand signals, use a click as a well-timed marker for the exact behavior you are looking for, and reward with food, praise or play, and you can train a dog very fast.
So how do you get a strong click without a clicker? Simple -- use your mouth.
I click in a manner that is not so very different from that used by the Bushmen (San or Khoisan) people of South Africa for one of their basic clicks. I press my tongue against the roof of my mouth until it makes a little vacuum, and when I pull it away (pushing forward sightly), it makes a loud popping sound almost identical to that of a store-bought clicker.
And here's the best part: I can never lose it!
Below is a video of the great Miriam Makeba doing the "Click Song" in 1966. The language here is Xhosa -- the second or third most common language in South Africa, and one which has embraced three types of Khoisan clicks as an integral part of its structure.