How do I tell him I want anal?

So I have a few butt plugs and I love having a finger/plug in my ass when I masturbate. But I haven’t told my SO of 9 months any of this because I’m afraid he’ll think I’m a freak… He was very vanilla before we met and I’ve slowly gotten him to be more dominant in bed, and he realized he actually loves being dominant and rough. But I’m afraid he’ll think it’s too kinky