When a person sees a vividly inapropro image as a young child, this may leave a mark on the young ones life. The young one might have seen his parents (or watched someone else) perform sexual intercourse which, at his/her age, the young one can't comprehend or process through their brain. All the young one knows is that he is scared as shit and will never see his parents the same way. Thus the child is mentally scarred.
ex. Little Timmy saw his parents having sex christmas night. They finally found him in the corner, rocking himself and mentally scarred.
by paddy_not_from_ireland March 24, 2014
He was mentally scarred when he looked up shocker
by Con90 March 22, 2014