How to quickly train your dog not to bark

Luk, my Doberman mix, happens to be quite the vocal puppy when he wants something, like to go outside, again, and again, for no good reason.  Why? because he'll come back two seconds after; he just likes to make rounds on his squirrel territory.

It's become quite a pesky thing, this thing he does.

One day I decided to borrow a trick out of "Mom's Book of Tricks" and put my index finger up in the air saying "ONE".
Then, after he barked again, "TWO"
and again: "THREE"
At which point Luk was grabbed by the collar and calmly walked over to the guest bathroom.

After he came down, he was let back out.

After several trips to the bathroom he put two and two together:

bark = finger in the air
three fingers in the air = time out


Now, I only count to ONE
TWO tops:)
Okay, okay, once in a while THREE is used as well:)