If you are trying to take a stool sample from your dog, you have the following options: You can ask your vet for a special container for stool. He will show you how to fill it properly. Don’t worry, the procedure is clean and be done easily. But, there is a do-it-yourself method. First, pull an inverted plastic bag over your hand, pick up the stool with your hand that is now covered with the plastic bag, then turn the bag right-side out by pulling the edge bag back over your hand, thereby securing the sample inside the plastic bag. After you have collected your dog’s stool inside the bag, place the bag inside a sealable container and hand it to your vet for testing.