Hier iemand die denkt het te weten:
Seems like Rig-a-Jig-Jig is an expression used in a famous song for kids. Rig may mean "improvise" and the Jig is the name of a dance, so it may be an expression to tell "Let's dance" or something like that ?
http://www.okwave.com/arigato/en/posts/12535
Gewoon even een beetje googlen, hè!