A fat person. Not someone who has the genetic predisposition for obesity, but someone who, through poor diet and lack of exercise, has become a soft, floppy, pile of blubber.
Side bar: these people are generally the ones who, through moderate exercise, alcohol intake and diet correction can loose the tub...of goo.
The expelling of gas resulting in a low tone like that made by a tuba. Akin to a bugle fart but a much lower tone is produced when really pushing hard in order to hammer that sucker out.
My coworker just let out an enormous boomingtuba fart that literally shook my desk.