Tojo, your solution is simple: Either a.) get a new girlfriend who doesn't watch porn or b.) Don't watch porn.
Out of sight, out of mind. And in answer to the question, no. The last time I had concerns about the size of my joint was the very first time I had to take a public shower after gym class in 9th grade. Man, I was so self-concious before I dropped my towel. But you know what? Once I saw everyone else's I realized I had
nothing to be ashamed of.
As far as you're concerned, even if it is rather small, there are still ways to move her personal heaven and earth with it. And that's all that counts.