He doesn't quite manage not to wince at the fish breath, but he puts a brave face on it. He's seen (and smelt) worse, after all. Unfortunately, the problem lies in guessing the name. The teeth retracting, yes, that seems to be intentional, but in this case Julian's overactive mind is actually less helpful than a normal one would be - he's aware of far too many options.

"Er-- O? That's... sort of an 'o' shape. In the Terran Latin script, anyway. I suppose you don't really use that. Um. Mouth? Gums? ...tongue?"

The expression is that of a man with very little faith in any of his answers.