Contaminate the place with the cannabis odor. Take a old zip lock bag that has been in used for storage and is all covered in resin and such. Turn it inside out, but your hand in it and rub it on things everywhere you can. Have everyone you know smokes do it. Poor dog will alert on everything that was contaminated...too the point the handler will probably pull out the dog because it will look like it isn't able to concentrate.
Remember, the dogs go after smell. When everything smells, sit back and watch the fun.