The act of covering up bodily noises by purposely making a covering noise in order to mask the uncontrollable sounds.
Person 1: dude, I just had the best-tasting meal that was so bad for my digestion. It was a zero calorie dinner and now I'm body-ventriloquizing in order to cover up (fart stomach growl)...Wow!!! did you see that bird...holy smokes that was cool
Person 2: oh man, been there done that