TwirlyGirl.net
Pastease
Good sites.
It is also easy to make your own if you're at all crafty -- just cut the shape out of some canvas or duckcloth, but "exploded" so you can glue it together to make a slightly conical shape (for a circle it's a circle with a slit; for a star you have say an extra point and a slit so you can fold it over to the desired size/number of points). Use fabric glue to glue it together. Then cover with strip sequins, fabric, or whatever you like. Attach to boobie with eyelash glue, liquid latex, spirit gum, double-sided tape or any other skin-friendly adhesive of your liking.
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