If you use the bathroom on your own, you are in charge of checking if everything is going well.
How do you do that? You have to look in the toilet!
In the bathroom we pee, poop and take care of periods. It is your job to know if your pee and poop look okay. If you are a woman, you need to know if your periods come every month.
You are in charge of how often, how much, and what it looks like.