Turn off tongue collision. It's in one of the menus. Unfortunately, that's a common issue with models like this. It can be fixed by manually adjusting the colliders using AcidBubbles tool but apparently it's a very long, annoying process. I've not tried it out.
It's a great look! The only issue I am having is that there is no included genital diffuse texture, which makes the skin default there and not white like it should be. I checked for the texture and it does not exist.