I had (and still have) the same problem as you. So when my budd (did I spell it correctly?) started talking about... let's say guns and blood. I started to talk with him, and slowly I went on anime subjects, and than I started telling him about how many guns and blood there is in Hellsing. He listened, because I was talking about something he wanted to hear! Than, I showed him some pics, drawings and other stuff and than I said he could watch Hellsing with me at my place.
The end
Good method? You have to try with psychological methods - they work in 90% !

