I figured I'd share this just because it's sort of cool.
Sometimes an explanation pales in comparison to a computer render.

1 has an external light at the top of the stomach.
2 is with the stomach itself glowing white.
3 is with an external light and the orbs glowing with a tiny bit of stomach glow- next to none.
4 is with an external light and the stomach glowing and the orbs glowing. All glow lol
5 is with external light and the orbs glowing.

One of the issues with glowing internals is that stomachs are all encompassing, so if you make them glow, you're basically sitting in a light source. So there is no shading except where objects (say the prey's limbs) obstruct the light and cause shadows which would be small and hard to see (check out the liquid around the base of the orbs in 2). The stomach itself would be invisible because folds are defined by shadows. When the object itself is the light it won't have highlights or shadows.

To get a good glowing effect you have to have almost no glowing happening and a light source somewhere else to make the forms of the objects obvious and defined, like in number 3. That allows the folds of the stomach itself to retain some shadows, and the fluid absorbs some light and flashes it around and on the whole everything looks better.

In this vein, I also did some renders (not shown) with an almost velvet material on the stomach walls- it was brighter where it aimed at the camera and darker where it didn't, and the results were pretty cool as well. You could make out the forms of the folds better than you might with just pure glow.

As an artist light is everything, so any time you deal with a glowing effect it means really sitting and considering what will be effected by the glow- usually everything. It makes for a really cool effect, but it's very difficult to achieve so hopefully this helps someone! It sure gave me some ideas... thanks render engine. XD
Anyways, to be moved to scraps...