I have also heard about and been aware of them for years, but alas, I cannot figure out how they are more discrete than squatting in some out of the way place - I mean, let's face it girls, we have practice squatting, not so much with the standing, and the figuring out where said funnel goes and then - what? we have to try to get the drips out? I think I'll a) not climb big walls, b) ride, run and play where I can squat or find a potty, and c) not have to wonder what to do with drips...
yuk - it gets a thumbs down from me