You bend down to make more understable, and up to make overstable. Don't know why it works, but it does. Don't bend both ways, though. Only the way you want and then move to the next spot on the disc. Mine stay tuned indefiniteley. You're not trying to "beat up" the disc, just change the way it is shaped a bit. Bend it in 3-4 places around the rim and be done with it. Has worked on Z Crushes, H,E,S Illusions, Z Avenger, and E Spirit. This method really beats the tragic abuse people put their discs through to try and beat them in. This doesn't work for me with mids or putters, but for drivers, it's the shiznit!!!