blow job tips? he's too big

So I recently started sleeping with this guy (feels weird saying "this guy" cause were really close and good friends) and I've been to scared to give him a blow job because I know he's had more experience than I have but he's penis is really big (to me at least, 9 in. I think) and it's thick and Everything about me is really petite so I'm scared I'm just gonna embarrass myself lol and I know it's def not gonna fit in my mouth so ://// ??? Sos