The idea is to create a print block, by cutting out shapes and making marks in polystyrene - you can buy sheets online or round pizza bases work just as well!
The great thing is, once you have made a print block, you can produce as many images, in as many colours as you want from this one block - great for making enough Christmas cards for all the children in the class.
See below for an example of the blocks I made.
Get a large brush, and brush paint over the block, more than one colour if you want - turn it over onto the paper, press down and rub your hand over it, and lift off - ta dahh!
You can experiment printing onto different papers - music papers, newspaper, brown paper. Have fun!