Inside the perimeter. Used in Atlanta to let people know you live inside the 285 beltway or "Ther Perimeter". Opposite of OTP, Outside the Perimeter - of course.
Instant Throat Punch. That feeling you get when someone says or does something so annoying or rude and you instantly want to karate chop them in the throat.
In the pants, can be used as a sexual term when a guy sees a hot girl and declares to a buddy what he would like to do to her. Can also be used to state where you love someone.