Maybe they could add a tail wrapped around waist and super flaccid tail options, both should prevent or at least significantly reduce tail (push the cape out a tiny bit, although in OPs case I can imagine a slight "v" crease/fold would work wonders too).

Hiding a tail would obviously work too but imo that should be the last resort, since that'd be like saying you should have to hide an arm so you can fit into the gear- lol (part of your body)