@Corey thank you very much this was the solution!
btw this is the code i used to register the textures!
@SubscribeEvent
public static void TextureStiching(TextureStitchEvent.Pre event) {
TextureMap map = event.getMap();
map.registerSprite(new ResourceLocation(Reference.MOD_ID,"tail/tailskincolour"));
map.registerSprite(new ResourceLocation(Reference.MOD_ID,"tail/tailhaircolour"));
}
I remember looking at it once and going "how the fuck does this even work?" I was never able to back-trace the parts that I understood (each segment) back to another piece I understood (the world generator).
I wish you luck.