New York City-based trainer Carol Lea Benjamin, author of Dog Training in 10 Minutes (Howell Book House) says this trick is easy to teach, but your dog has to be willing to retrieve.
First, says Benjamin, you loosen a tissue so it’s sticking way out of the box. "Hold the box of tissues, waving the loosened tissue like it’s a flag. Make a big deal out of this tissue, encouraging the dog to take it. Act as if you’re presenting her with an all-new toy. When she expresses interest, encourage her further."
Some dogs will immediately snatch the tissue, others will take awhile to process what you’re telling them, and why. After all, they’re thinking, tissues have been around the house for years and mom’s never wanted me to do this before. When that breakthrough comes and your dog does take the tissue, praise like crazy.
Ask her to grab it again, and again. Now, Benjamin says, say "Aaaaachoo" as you wave the tissue flag. "The more dramatic the ‘Aachoo,’ the better," she says. "Be Sarah Bernhardt." Continue practicing, so your dog knows that when you say ‘Aachoo!’ it’s tissue-grabbing time. Gradually lower the volume of your ‘Aahchoo’ so it’s not quite so dramatic.
"A few days or weeks later, there you are at your fancy dinner party. You sneeze-or act like you’ve sneezed, and say ‘Aachoo.’ That’s when your pooch makes a beeline for the tissue box and brings you a tissue. Bravo!"
It’s easy to teach your dog to do this on any cue-not just ‘Aachoo’ can work. For example, you can say, "So sad." So when you begin to weep because Joey, Rachel, Ross, Phoebe, Chandler and Monica are no longer going to be on Thursday nights, and you say, "That’s so sad," your dog will fetch the tissue.
One note: Be sure the tissue box is anchored down, or the dog may not be able to pull out the tissue. You can fold over masking tape or use double-stick tape to anchor the box.