how do you describe it

-How do you describe it?
-What do you describe it as?

Are my sentences all correct? If yes, how come people tell me we can't say this?

-How should I call you (=What's you name/What should I call you)

====================
-What should I call you?
-You should call me John.

According to the above, is this possible?

-How should I call you?
-You should call me by my surname.