There are two reasons why a dog’s tongue is crooked outside the mouth. One is that the weather is too hot and the dog needs to stick out its tongue to dissipate heat; the other is caused by disease, which may be stroke, epilepsy, or poisoning. It's better to go to the hospital for a check-up. Some dogs will always have their tongues crooked outside their mouths as they get older. If it is because the weather is hot, you need to take your dog to a cool place and prepare enough water for your dog to avoid heatstroke.