There's a lot of bullshit talked about penis size, and particularly here people don't seem impressed unless you claim 8" or 9". That's not very reassuring for guys with 'only' 6". But in truth 6" is a good size and is probably well above average.
If you read up on recent penis surveys you'll see that the average erect penis is now thought to be around 5.5". That's based upon volunteers being measured by trained medical staff. I tend to think guys with really tiny cocks would be more reluctant to volunteer than guys with big cocks, so the average is probably smaller. Maybe nearer 5". So you'd better come to terms with the idea that with 6" you're actually rather well hung.
Compared to some of the bigger cocked porn stars (Ron Jeremy, Shane Diesel, etc.) yours will look a bit small, but c'mon, you're not talking about that situation. In the real world, where you want to have sex with someone, and you take your clothes off, you will not be laughed at unless you've chosen a complete idiot for a sexual partner.