I can't even fathom what you are telling me it's so insensitive of your BF! Rape is an unwanted, traumatic experience. He tells you it turns him on and wants you to call him your rapist's name? WTF! And you are able and willing to do that? And you ask if you should be worried that there is something wrong with him for wanting this?

How do you feel about doing this? Are you comfortable with it? Yes, there is something very strange going on here!

My intentions are to be supportive to you, but as someone who was raped (date raped), I just have to shout What are you doing?