Why talk on the phone with your pants down? Because if you don't have the thing in your hand, it might fall out of your pocket or holder into the drink.
I'm scared to my wits to use a porta potty at the races. Normally at a job I can leave the phone somewhere outside the thing. I won't go in there with it on my person.
I think you can safely piss with the phone put away. In fact, two hands are usually needed to unzip. I suppose ear buds or a cricket could be used while whizzing.
Flush away.
