I'm pretty lucky I guess, but I can choose to keep my foreskin pulled over my head or keep it retracted where it won't pull back up, especially if it's growing... so when I put on a condom I'm usually bigger and already keep the foreskin retracted... if that makes sense
Obviously the guy on the left is way bigger than just about everybody. I think 6 inches is when they start looking big. I like this pic because of how similar your heads look to each other.