A girl next door is basically someone that is sweet, wholesome, and an easy going person. She is the girl that has no one looking at her because the whores with big boobs get the guys first. She is very shy and modest but when she is yours she is a cougar in the sheets.
Bob: Do you see that hot girl?
G:(thinking) Does he even notice I'm right here? maybe I shouldn't be the girl next door anymore.