I sometimes get the urge to cut off limbs
Are you talking about actually cutting off your own limbs, in the physical sense?
Yes, I dream about cutting my own limbs sometimes
I'm sorry you are feeling this way, it can't be easy. It is wrong to harm yourself and you should think about getting some medical help. I hope you are able to reach out to someone about your thoughts and about these desires.
I was only joking, don't act like this is a big deal! Jesus Christ!
Okay, I'm glad to see that the joke was on me all along.  However, you should know that some people really do feel an intense urge to hurt themselves, even severely, and in this job, we have to be ready to help.