First of all borrow your buddies driver. Then get him to hold a piece of 2 x 4 about 2 inches over a teed up golf ball and parallel with your stance. Take a rip at it and try make the club come under the wood. If you do the outside in swing which cause most slices, you'll hit the 2 x 4. If you make the proper inside out swing you will rip the ball right out from under it and hit it straight or with a draw. It will probably bust the shaft on the driver after a couple of misses, thus the reason for borrowing your buddies driver. BUT, it won't take long to correct it!!!! PS, Use something a little softer, like a piece of foam or something. This really works very well in promoting that inside out swing.