Watch the Flutters online guitar lesson by Chris Buono from 60 Electric Guitar Techniques You MUST Know
Flutters are about as ornamental as any electric guitar technique can get, and that's just fine by me. Flicking the bar upwards and abruptly letting go causes the tremolo spring system to convulse for a split second. The resultant sound is a sort of gurgling that always snaps heads.
Looking for inspiration? Steve Vai and Jeff Beck might as well be the poster boys for whammy bar antics, and flutters are definitely one of their more infamous activities.