Shake to Shuffle is a feature that is found on the iPhone, iPod Nano, iPod Touch. The next time you’re listening to your music and you want to listen to the next song before the one your listening to is finished you simply shake your device and the next song will start playing so you just shake to shuffle to a different song in your music library. Cool and easy to do!
If you want to turn off the Shake and Shuffle Option you can.
iPod nano (4th generation), iPod nano (5th generation), iPod nano (6th generation)
Shake can be disabled in two ways to prevent accidental activation of the feature: