Yeah but wasn't his excuse that he lost it in battle or something? (i genuinely don't remember). That ain't gonna work with a literal infant. Dumbass is about to (best case... well, best case if it comes out tail-less) make his kid into a social outcast or (worst case) it'll lead to him getting found out and then the whole damn clan gets turned into social pariahs and/or killed.
No, it was just that he's the type of dragon that's shy about his tail, or something to that effect. It's actually noted during their first outing to the city that not all dragons like to have their tails showing, they even have tailless outfits to accommodate that. That being said one has to wonder if that's just because there are a lot more dragons mingling with humans than either race realizes and all those dragons that "don't like to show their tails" are really just other dragons also hiding who their partner is, now that'd be quite the twist.
Either way, I imagine it's something like how not everyone is comfortable showing off their legs or some guys are fine going shirtless while others find it uncomfortable to do so even when swimming or like the difference between seeing exposing your midriff as ok vs seeing it as indecent, or something to that effect. Or it could just simply be that some dragons have a complex about how their tails compare to their peers, which ironically means that he's labeling himself as having reason to feel inferior to his dragon peers 🤔