Mysterious water

I've started trying to swim for exercise. It is low impact, which is great for outrageously oversized people, plus it is way more fun than running, walking or lifting heavy weights. However, the other day I waddled out of the pool into the men's locker room and bent over to take off my swim trunks. As I did, from nowhere a half of cup of water splashed on the floor at my feet. I froze in terror. I had no idea where all this water suddenly came from. I knew it was impossible, but for a second I thought I might be pregnant and my water had just broke. Where did all this water come from?! After a few moments of unrequisite terror and alarm it dawned on me... my belly button. I'd just been carried a child's sippy-cup full of water from the pool to the locker room without spilling it...until I bent over. Suddenly I was very glad no one was around. Now I'm starting to wonder what else I can store in there....