During these cold winter months, no one (your dog included!) is going to want to be standing outside for long periods of time. That’s why this “eliminating on command” trick will be perfect for the chilly temps! This command (also known as “park”) is not as hard as you might think and it will probably become one of your most used tricks. You will need to use the “click and treat” process here.
Here are the steps on teaching your dog to eliminate when you tell him or her to do so: http://www.doggiebuddy.com/topics/tricks/park.html
Step 1: Choose a specific spot where you want your dog to eliminate.
Step 2: After he or she finishes eliminating in that location, click and treat.
Step 3: Every time your dog eliminates in that specific spot, click and treat. Introduce a command that you want to assign, such as, “park” or “potty.” It is up to you, but you should keep it simple and something you know you will only use for this specific command.
Step 4: Be consistent, but vary the reward so your dog doesn’t get bored and loses motivation.