alcohol will cause vasodilation, some bodybuilders drink a glass of wine before stepping onstage to up the vascularity (and probably take the edge off)
niacin causes whats called a niacin flush, where you get vasodilation as well all over. you get a warm sensation and skin appears slightly pink to red, some people even get splotchy.
both, temporary methods at best.
heat, food intake, and low bodyfat will bring things out nicely in most cases.