Use an Incognito Window to Allow Students to Present from Your Computer | TIC & Educación | Scoop.it
From www.alicekeeler.com - July 17, 2013 3:49 PM

Problem: Your teacher computer is connected to the VGA cable to the projector. Students are doing presentations and need to log into their Google account to get to their presentation they are going to do in front of the class. You have to log out of your Google account to let them log in.