So, there's not much to say here, except some fun facts:
Polaris's insides smell like oily lemons.
While Polaris does have the normal black insides, his saliva also glows yellow. You can see it in the picture here, how much it glows.
The Stellar Dragon digestion is powerful enough that the prey's nerves are destroyed so quickly that there's very little pain. To prey, the feeling isn't like sleeping gas; it's more like sarin, but a lot weaker than that. In regards to smell, it will vary from individual to individual, but more oily than sour, and of course smells like whatever they've just eaten.
While the structure of the stellar dragons' systems are normal, their insides have very powerful digestion, that can reduce metal down into small chunks, and also dissolve flesh and leave completely transparent waste.