Bottomless pants

I had heard, but never seen, these - baby's pants with no bottom ! The kid can just poop or whatever, whenever and wherever they want ! A bit of a strange sight on the subway, but it turns out of course, that this is quite common on many countries. Now, you might wonder, as I did, how you keep said child from pooping in the subway. Turns out that this entire process is called "Elimination Communication" or "Natural Infant Hygiene" - see this WikiPedia Article on it. There is even a website dedicated to this process. Basically you start teaching the child at birth to signal when it is necessary to use that giant hole in the pants. Lots of verbal and hand queues, etc. Interesting.