The cat might come over and meow while you're using the toilet for the following reasons:
Curiosity: Cats are very curious about their owners' behavior. If you are sitting on the toilet for a long time, your cat may come over to see what you are doing out of curiosity.
Dependence: Cats are usually quite dependent on their owners. If your cat meows next to you while you are using the toilet, it may be hoping for your company or needing your attention and comfort.
Habitual: Some cats may associate squatting with a certain behavior. For example, some cats may associate their owner squatting with the owner being fed, and believe that they should also get food.
Loneliness: If you often leave your cat home alone, it may feel lonely and bored while you are using the toilet and wish you could keep it company.
