my uneducated opinion...
inside out means hitting a forehand from the backhand side of the court to the opponents backhand (assuming both right-handed players).
At contact the strings (racquet face) point to where the ball will go, regardless of if you are pulling, pushing, keeping the racquet stationary or moving it from side to side or up to down. as long as the strings are pointing to the opponents backhand the ball will go there. remember, the ball is moving towards you, it will bounce off your strings and head to where the strings are pointed.
of course, if you want your forehand to be more than just a dink stroke, you will need rotation and/or extension through the ball, but you can hit inside out without moving the racquet as long as the ball is coming to you strongly enough.
Disclaimer: I'm NOT a coach...
Real tennis: https://www.youtube.com/watch?v=yDqnkLJ9BtM
Last edited by Relinquis; 01-09-2013 at 03:11 PM.
Reason: added (racquet face) to clarify