Well, after having fought Bubble's Velvet yesterday as a Tianhuo player myself who's been trying to focus more on neutral play (and having experience with Keet's/MPK's Velvet too), you basically have two main jobs as a Velvet player.
A) Recognizing the Tianhuo's player attacking pattern to block it properly because otherwise you will probably get opened up at some point.
B) Know how to properly move in the screen so that you'll be able to stay out of her range and only when you feel you have the upper hand you might try to make the Tian player start blocking themselves.
It's a very patient trying matchup as a whole. Both for the Tianhuo player to be able to open up the Velvet player, and for the Velvet player to be able to block all of those advances. You have to pay close attention to both your and their magic bars so that you'll know when you can use your strongest tools, and when they can start applying way more pressure. Knowing what can a Tianhuo player do in the air, between superjump, flying and airdashing, as well as the ranges of both j.C and j.B from her will probably help you a lot.
That's the best advice I could probably give you, and if you work on defense yourself, you'll probably be able to handle it much better, but it does take practice.