Ever heard of the Septic Dance?

So my friend said to me:

'Ever heard of the Septic Dance?'

  I said 'No' because of course I never had and I asked what it was about.
  'The Septic dance!!!  It is the thing everyone is into these days!'
  'Truly?  Now that is fascinating!  How does it go?'

And then my friend showed me this....