If the dog is indeed fear aggressive, leash corrections will only increase the fear and resulting aggression.

If the dog is naturally timid and shy and rather undersocialized, corrections are not necessary and not recommended. Rather than correcting the dog, find a way to make it a positive experience. It's harder, but it's better in the long run. For example, I could smack my dog every time he peed in the house or I can teach him to sit by the door and ring a bell. I wonder which option would make both of us happier...