Have you installed VRCFury? That could be the issue or if you do not have the latest VRC SDK. Otherwise is there anything unique about the avatar that could mean VRCFury is not able to find the avatar hands. My DMs are open on discord if you needed more help to troubleshoot what the issue could be.
Viewing post in 3D Canine Dildo with interaction comments
https://discord.gg/rdwrXW2b is my discord, I have a Adult asset section. Or you can DM me, name is just Wuffwick