Start with a one and a half mount as in Buddha's Revenge.

Just as you are going into the one and a half mount pinch the string with your throwhand just above the yo-yo itself. As you pinch allow the yo-yo to swing in the direction it was swinging when you went into the one and a half mount. By pinching a loop should be created that will follow the yo-yo around as you swing it. The first swing goes on the far side of your body, and the second goes on the inside of your arm.
Note: It is very important to do this in one general motion in order to create the proper loop.