Sexual sadism disorder is a condition where a person gets sexual pleasure from causing pain or suffering to another person. This means that they enjoy hurting someone else in a sexual way.
Imagine you are playing with your toys and you like to play rough sometimes. You might pretend that your toy is being hurt or in pain, but that's just pretend. With sexual sadism disorder, an adult person might enjoy hurting someone for real, and it gives them pleasure.
This can be scary for the person who is being hurt, and it's not okay to hurt someone without their permission. It's important to remember that hurting someone else on purpose is never okay, and if you or anyone you know is experiencing this, it's important to talk to a grown-up or a professional who can help.