A species of humanoid foxes from Trials in Tainted Space home to the mostly oceanic planet of Arcysus (the homeworld of the Kui-tan, Jitafore, is a moon orbiting them). Besides the ears, talons and tail(s) expected from a fox humanoid, Sionach also possess a pair of horns. Their long tails vary in numbers from 1 to 9, are prehensile and glow gently in the dark thanks to luminescent glands in the tips.
While Sionach females are equipped with the same genitals as human ones (albeit with smaller breasts) males possess external phalluses, which are normally concealed inside a sheath. Sionach cocks are knotted, but lack the distinctive tapered shape of an actual vulpine phallus, instead the sionach phallus has a distinctly bulbous, reptilian shape to it. Male phallus size is abnormally large compared to their body height, with average lengths between ten and eighteen inches.
Complex organs inside of the Sionach's torso produce a strange chemical mixture that becomes luminescent several seconds after being exposed to oxygen, creating a ghostly looking flame.
Despite their otherwise mammalian physiques, Sionach actually lay eggs.

For more information: https://wiki.smutosaur.us/TiTS/Sionach