"Use your words" is one of those phrases that gets thrown around a lot as advice to people who tend to express themselves through physical actions like punching and biting rather than saying how they feel. (That includes toddlers and soccer hooligans.) It's a generally solid approach and one that could ease tensions not just on the playground and in the stands, but also in a wide variety of other settings. A shared or public bathroom is not one of those settings.
Unless you happened to fall into the commode after somebody forgot to put the seat down and you need to call for help, leave the phone conversations until after you've taken care of business. The person in the next stall doesn't want to hear you making dinner reservations or gossiping about your neighbors while he or she is popping a squat. And whoever is on the other end of the line probably doesn't want to hear the sound of you or your neighbor flushing the toilet either. Not the mental image they want to have while talking to you. Which brings us to the next item on our list.