My boyfriend loves it when I give him head. I do it pretty much every time we have sex or get sexual.  However he doesn't like going down on a girl. He doesn't like the way it tastes he said and that he doesn't like doing it because that was all one of his exes would do with him. We've been together for almost a year and he's never gone down on me. I've brought it up but he just laughs and shakes it off. How can I get him to just try it once with me?