Yeah, that's what the tag is mostly comprised of, but there's 9 or so images in the tag referring to this kind of bulge. I'd go ahead and make a new tag for it (stomach_bulge maybe?) but I'm not sure if one already exists or not. I'd be hard-pressed to believe there were only 10 of these images on the site.
No. That's something entirely different, referring to the inflation of the stomach through excessive injection of some form of liquid: water, cum, etc. I'll go about separating them now.