--INSTRUCTIONS--
1). Replace your kfn with the respective model, (sfw to sfw, nsfw to nsfw). Make sure you have the novabeast maw installed to have the materials and animations.
2). There will be an extra set of bones from the neck up. Unpack your nova and drag the neck to neck, head to head, and don't touch the tongue bones.
3). Great news, you're already almost done. Just slide in the materials, and you're set (kinda).
4). Go and make a bunch of vrcfury toggles, each for whatever you want. If you want the maw to have an animation, make an animation toggle and put in the maw breathing animation.
5). Toss in whatever other animations you'd like, you can easily make these using vrc fury. I made some for opening the maw and sticking the tongue out.
6). For animations you make that stick the tongue out, MAKE SURE you have the tongue physbones disabled by default.
7). Test and see if you're all set.

--EXTRA--

Here are my tongue physbone settings, but you don't need to copy them exactly, have fun with it.

If you need help, simply ask and I can try my best.