Sometimes it does and sometimes it doesn't. I don't think there is a trick to it either...I just think it has to do with the ingredients of the puffy paint. The bigger drops don't flatten much, so maybe that is the trick, but making home-made bling...you can't always make them big drops. Once it dries and is attached to your page though, I don't think you can tell a difference between it and the store bought kind.
I have lots pics of my homemade bling in my gallery, on my blog, and in my etsy shop...you can take a look at the finished product and see if it is something you'd like to try.