When you're in the studio, turn off your cell phone. There is nothing to be gained by allowing the outside world to interrupt your genius. Focus on the music and let the moment unfold with your undivided attention.
If you use your phone for lyrics or notes, that's obviously something you need handy. Just move it into airplane mode and resist the temptation to play any games. If you take photos with your phone, save the social media sharing for after the session. Unfocused time in the studio is wasted time in the studio.