Adam Levine has “stopped farting in front of Christina Aguilera” while filming “The Voice.”  The Maroon 5 singer … who mentors on the show alongside Aguilera, Cee Lo Green and Blake Shelton – decided to improve his manners when he realized that Christina is surrounded by males when she shoots the show.  He told Rolling Stone magazine: “I honestly just recently started realizing that you’re surrounded by three dudes all the time, and that has to be something of a pain in the ass.  We stopped farting in front of her!”