phrases - Talking out of the side of your mouth

Talking out of the side of your mouth

This means one is lying, right? Or something else?

Answer

It means trying to keep a heated or private conversation private in a place where there's a risk that it may be heard, as Robusto suggested. Check this out: http://www.youtube.com/watch?v=cUKJWsnAAXs&feature=related&t=1m03s (one minute and 3 seconds).