metalic

I have a customer wanting metalic on the next set of screen printed shirts. I do the artwork and was wondering are there any rules for using metalic? Like use only as highlightes, don't use on text, or only use it on certain material and colors. The t-shirts are black and the ink colors are white and hot pink. It's just a huge star with a silhouette of a ballerina in the middle of the star along with some text. Any suggestions will be great, so that my screenprinter's artist won't call me out on this whole metalic thingy. Thanks, Blee