>>297860868
>weight paint
See this is why I asked. I didn't do anything related to blender with the dick model. I just got the fbx, put it in unity, and slapped it on my avatar. Well, and added the textures/shader obviously. I treated it like I would any "Accessory" that goes attached to my body. I have never had to use blender/weight painting for an accessory?

>>297861391
It does have dynamic bones. 
> if the hip is the pivot point, the dong will float around like that
This might be the issue, actually. I'd have to try changing it so it doesn't pivot around it, how would I go about fixing that?