Hi, have you tryied my Futa/Penis mod already? https://www.loverslab.com/files/file/30962-surverx-zombi-cocks-for-val-karee/

You can choose to apply 3 separate mods (or only one of them...):

1. big penis for the zombies

2. penis for the green goblin

3. Futa for gemini

... have fun with this nice game :-)