This smells like a Monzetsu pic.

Monzetsu Curriculum, I think. First story, second half. >.>

There's a name for this, uh, belly extending due to cock thing, I think.
I think it deserves a tag, it's not unusual.
But what to call it?

I believe they are typically tagged as "bulge".

Hmm, I don't think that's it. If I remember correctly, bulge is the form of penis, usually futa, seen through tight clothes. This is something else.

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.

Let's name it stomach_bulge for now.
If a better name turns up, we'll switch it then.

the term is "inflation"

That term conjures up a different picture in my mind.

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.

Distension? I think that's it if anyone can 2nd me.

Wowzers.

"wowzers"? there's a single japanese symbol for that? @_@ my respect for hentai artists everywhere grows...