The truth is baby's come out of there, so it can fit a lot. But the last thing I like to be thinking is if she need to have an epidural block just to get my dick wet. Some times its funny but its not sexy.
Real life porn needs bigger dicks otherwise you would have trouble seeing them. In porn games, you can move the camera into impossible locations so you could have a game with a small penis. But, since I am usually the one with a dick in the game, I want a bigger than average one. However, too big breaks suspension of disbelief. I would rather the dick shoot off fireworks, glow in the dark, and have sound effects, then to be the size of a baseball bat.