It doesn't take much apparently. Just chew on about a ringgit's worth of some stiff keropok lekor a day and you're good to go. I had some right after Friday prayers just now (near Masjid Mujahidin, Damansara Utama) and I already can't feel my jaws. I'm thinking chewing on those Wrigley's chewing gums for jaw exercises are for wussies now.