Ok, what is the average size in a guy's manhood erected?

I have had several girls tell me on how well I got there rocks off and comment that I have it where it counts. It makes me good about myself but I'm not the one to go around boasting about it so I just keep it to myself. But I'm not about to go around and say "Dude, let's compare our stuff" to see if I do have it where it counts. So ladies if you could- What is a good size for a guy in your opinions?