Creating a freezer paper stencil is super easy; just follow the steps listed in this graphic! Creating a confetti design should be fairly simple ... have fun hand drawing your own to fit on the front of your shirt, then cut out the designs with a craft knife to create a stencil. After you iron the freezer paper stencil in place, make sure to cover any exposed areas of the shirt with paper towels or more freezer paper to protect from potential overspray.
When spraying ColorShot, make sure to spray several light coats instead of one heavy coat to help prevent color from bleeding under your stencil. Let dry in between coats, and when you are happy with your color coverage, go ahead and remove the stencil and let your shirt dry completely.