In the big city we are all busy busy busy, right? Running here and there, to and fro, getting it all done, seeing and being seen. Hydrating is essential when you’re on the go (and even when you’re sitting still) but the downside to being well hydrated, is that you will eventually have to, ahem, relieve yourself. Forgive me for descending into potty talk, but when you gotta go, you gotta go.  And if you’re out and about, there might not be a convenient restroom nearby. What to do, what …