I have a dear friend who's name is The magical Fairy Crystal, she goes to birthday parties and helps children have fun.  I helped her make a video a few years back and this is a recipie she shared with everyone who watched her movie, and now I will share it with you.

Faerie Crystalls Sparkle Puffs
You Will Need
Large Mixing Bowl    Mixing Spoon
Dessert Spoon        Plate
Bowl for sprinkles
Marie or Choc chip biscuits
Sweetened Condensed Milk
1 Table spoon Cocoa
Sprinkles
Time,15-20 minutes including cleaning up.
Crush the biscuits finely, (I have found that placing the biscuits into a LARGE zip lock bag (squeeze air out prior to sealing) and using a tenderising mallet is an excellent mess free way to crush them).

 Add Cocoa and then Condensed Milk.  Mix until a thick a sticky consistency with all biscuit coated. 

Use a dessert spoon to portion out the amounts and roll into balls using the palm of your hand.  Roll the balls in sprinkles until well coated and when whole batch is done, refrigerate.

Lick fingers thoroughly, then wash all dishes, they are ready to eat in about 15 minutes.

(I have found that if you want to make something like this for a really quick yummy snack or a birthday party but can't deal with the messy hands, simply put baking paper onto a slice tray, up the bowl onto the tray and with a wet hand press it all down and refridgerate, then you can slice it into bite size bits, you can ice it first if you want and I have been known to add choc chips to mine as well..........Putting jelly on top doesn't work, after a day it all goes soggy, (okay, if eaten as soon as jelly is set though) (Trial and error)