I HATE Benetint! maybe it's the way my lips are, but the stain is so liquid-y that it settles in the middle of my lip - like I've eaten a popsicle. But the outsides of my lip are normal color. I prefer Urban Decay's ink stain:
http://urbandecay.com/categories/InkLipStain.cfm
It comes in a pen form and is fairly easy to apply. I go light on it though because it's definitely color intense. It lasts for a really long time too! No need to re-apply.