It depends on which liquid liner you are using, because some are not safe to put on the waterline. I believe MAC's LiquidLast is not safe for the waterline (could be wrong, please correct me if I am), and neither is their Fluidline (not exactly liquid, but...yeah). In my experience it's more trouble than it's worth, I have to peel my eyelid away from my eye until it dries or else it like, osmoses with my eye juices so my eye is full of black eyeliner. I also like the harsh look, so I just use MAC PowerPoint pencil with some Carbon eyeshadow on top.