It's not 'all in the hips' or the knees for that matter.
Wiggling IMO starts from within - you've got to lose your inhibitions first!
Then you need to use a combination of feet, ankles, knees, hips and abdominal muscles to get your body wiggling - just be sure to move them all in the right order and orientation otherwise you'll look like you're having a siezure... I agree with Spin Dr - find someone whose wiggle you like and practise with them...
S. x