Why you peeing in that thing, bro? The two big arches ought to be enough for any halfway intelligent person to realize that you’re supposed to stick your buttocks there not your beanie-weenie. Dries out your logs so that they don’t make as big a mess when you pick them up to toss them into the sink.
If I were going to use a dye on my skin for something like this, I would first test it out on a small patch of skin some place where nobody’s ever going to see it, like on my penis.