The reason why dogs like to sleep in the toilet may be because the toilet is a quiet place, and sometimes the floor of the toilet may be cooler, making the dog feel comfortable. In addition, dogs may also like to sleep in the toilet because they have a natural survival instinct and want to be alert at all times so that they can escape quickly when danger arises. So if your dog can stay alert in a quiet toilet, he may be more willing to sleep there.
However, if your dog often sleeps in the toilet, you should also pay attention to its health. Sometimes, dogs like to sleep in the toilet because they are not feeling well, such as having a cold or fever. If you find that your dog frequently sleeps in the toilet and is accompanied by other unusual symptoms, you should take him to the veterinarian.