Has anyone ever done clay or ink hand and foot prints?

For clay, what clay product or recipe did you use?

For ink, did you use an ink pad or "magic ink" (it goes on clear and prints black on special paper)?

I was thinking about trying it with the Crayola air dry clay used here: http://learningaswearegrowing.blogspot.com/2012/04/diy-clay-hand-prints.html

Also, any tips on getting a squirmy baby to cooperate?