bj tips for big dick

So there's this guy I have a thing with and we were sexing last night in Snapchat and he was sending me videos of him jacking off and I had heard the his dick was big but I didn't realize how big until I saw it😂 it's 9" and pretty thick so does anyone have tips for how to give a guy with a bigger dick a better blow job? (I've never given a blow job before at all)