What's the best type of pen for autographing a T-shirt?

As the title pretty much points out I'm trying to figure out the best thing to get a T-Shirt autographed with. I think the shirt is cotton. It seems that a fabric pen is better than a plain ol sharpie from what I've read but there are still so many brands of fabric pens not to mention different kinds of tips with the pens that I'm kind of at a loss. Can anybody offer any suggestions of good or bad?

Assuming your not trying to pull one on me. That's unusual, never heard that before. Still, also wondering what would be the easiest tip to autograph a shirt with. I assume a fat tip would not be preferable.

The absolute best would have to be felt tip sewing markers, use a sharpie like every other rock star. , bring a few extra incase you loose one and have metallic if your groupie is we reign dark colors.