There is a product called Liquid Applique that comes in a tube and you apply it much like glitter glue; let it dry and then you use a heat gun to make it puff up. (I used it on
This Card on the fur trim.)
If you are going to Michaels and venture out of the stamping aisle into the area with the t-shirts to decorate, Tulip makes a fabric paint that puffs up. I'm not sure if that one needs the heat to make it puff up, though.
There is also paint from Deco Art called a Snow Writer, which comes in a tube with a pen tip and is dimensional. I haven't tried that one, although it is on my list