Ask a Basterd: Can I Talk on the Phone While Taking a Whiz?
http://www.wired.com/culture/lifestyle/magazine/17-08/by_ask_whiz
"No, you can't talk on the phone! Do you want the guy next to you to hear your entire conversation? That's why you should only text in the bathroom. Just be sure you don't hit the wrong button and end up putting a photo of your junk on Twitter. Trust me, you don't want those followers."