To do it I just cut out the mustache shape with my Silhouette, taped the negative to my onesie, and then filled it in with bling. Then I went ahead and heated up the bling (to activate the adhesive on the backside of it) by placing a paper towel over it and then ironing it. -I could have used my i-rock on it too...but I was in a rush. -Once done I just removed the template.
And then you have a fun mustache mask to play with. ;)