Dogs love to roll in any stinky thing they can find, from animal droppings to dead fish. When that happens, it's definitely bath time!
Bath time doesn't have to be a wrestling match. Teach your dog that the bath site—probably the bath tub for medium and large dogs, maybe the kitchen sink for small dogs—isn't a scary place.
Put the dog in the tub or sink, give him a treat, praise him, and cuddle him gently. When he relaxes a little, take him out of the tub. Don't make a fuss about him or give him a treat after he's out—you want him to associate the goodies with the tub, not with escaping from it. Do this once or twice a day for a while, slowly increasing the time he has to stay in the tub. Pretty soon he'll look forward to tub time. Next, put a little lukewarm water in the tub so he gets his feet wet when he gets in, and reward him again with treats, praise, and petting. When he accepts that routine, wet him a little with lukewarm water from a sprayer or by pouring water onto him from an unbreakable container. Follow the same routine—begin with a short time, reward him, and slowly increase the time. Soon you'll have a dog that likes to get into the tub. This approach takes a little time up front, but it sure beats having to wrestle a dog into a bath for the rest of his life.
Now your dog is ready for a real bath. Assemble everything you'll need. Brush your dog to remove loose hair, tangles, and mats. Get your dog into the tub—and don't forget to reward him. Consider fastening a grooming loop in the tub so that you can tie your dog. You don't need a sudsy, wet dog making a break for it! Insert a cotton ball shallowly into each ear to protect the ear canal against water. Apply an ophthalmic ointment (available from your vet or a pet supply company) to the eyes to protect them from soap burns.
Don't use shampoos meant for people on your dog. The pH balance is wrong and will damage the dog's skin and coat. If your dog has a skin condition, your veterinarian may recommend a medicated shampoo. If you're concerned about killing fleas, wet and lather the dog thoroughly, beginning with a “collar” of lather high around the neck to prevent fleas from moving forward to hide in the ears. Leave the lather on for about 10 minutes (be sure the bathroom is warm so your dog doesn't get chilled) and then rinse. The wet lather will drown any passengers without exposing you and your dog to toxic chemicals.
Wet your dog thoroughly using lukewarm water. Cold water can chill your dog, and shampoo won't work as well in cold water. On the other hand, most dogs don't care for a hot bath. Apply shampoo and work it in with your fingers, or apply shampoo to a net bath sponge and use that to wash the dog, working over the body in the direction of hair growth. Begin at the neck and work to the tail. Don't forget the belly and up under the hind legs. Use a washcloth for more control when washing the face, and be careful not to get shampoo in your dog's eyes.
Rinse your dog thoroughly. Don't forget between his toes, his armpits, groin, and belly (there is a groove between the ribs on the bellies of dogs in proper weight, and soap loves to hide in there). Go over his body with your hands after rinsing to be sure you got all the soap. If you hit a slimy, slippery spot, that's soap, so rinse again. Soap residue can cause serious skin irritations, so be sure you get it all. Gently squeeze excess water from his coat. Then towel. If your dog has a short coat, rub vigorously with the towel, finishing up by smoothing it in the direction of growth. If he has longer hair, pat dry or press sections of his coat with the towel to avoid creating tangles.
Before you let your dog out of the tub, praise him and give him another treat for being so good. Now carefully release. Don't let him leap wildly—he could slip and scare or injure himself. You may want to put a leash on him—most dogs have “crazy dog attacks” after their baths, and they like to run and roll and rub themselves on things (carpets, couches, bedspreads …).
You can blow dry your dog if you like, but don't use a hot setting—it will dry out his skin and coat. Otherwise, crate your dog or confine him to a specific room until he's dry. If he needs to go out, take him on a leash—dogs love to roll on the ground when wet, and they're regular dirt magnets. Be sure to keep your dog warm and out of drafts until he's dry.