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.
Gawd, that is one tubagoo.
So this guy shows up on the date and (she) could not believehow much of a tubagoo he had become!
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.