1) Buy child a keyboard. They are happy. They love playing the demo songs and bashing the keys in a "musical" fashion. Who knows, they may be the next Mozart. All is good.
2) Groove out to the "chooooons" in the style of a drunk over energetic Dad at a wedding disco and allow yourself to be caught on film. Whilst grooving make sure you are in your pjs with bed hair. In no way should you look cool or attractive (props may be given for the Threadless "Rock out with my Cock out" tee which is at the same time funky and appropriate).
3) Upload the video of your "dance". Have no shame. Rest assured that in years to come your child will be jeered at all the way through school for having "the Mum who did that dance".
Simple really! (I have no shame, it is true).