They want to shock you. It is common for young people to test their parents. Words related to sexuality that are fine with friends may not be okay at school, home, or work. I WANT TO GIVE Decide on a response that gets your message across and teaches what you want your child to learn. It is not nice to hurt someone's feelings with words.
Every family has different standards about language.
That kind of talk is not okay in our family. If I hear you say that again, I am going to punish you. I find that language ugly and hurtful. Let's talk about that word and why it is used. I am upset to hear you using it.