As a black girl who's dated white men for the most part, I think I can help out here. First, not all black guys have monster dicks so let's just get that out there. Second, not everyone prefers a monster dick. And not all men when huge dicks know what to do with it. I've had the most intense and satisfying orgasms with average sized dicks FYI. It's more about who it's attached to and your level of comfort with one another Third, get out of your head and stop making these assumptions! If you're that worried about performance anxiety, just have this convo with her straight up. Something tells me she'll help you get past this really quick with the newfound insight