It will make you happy (?) to know that "robodick" appears to be the consensus
This search led to some places I should have expected it to lead. Darker than any vore fanfic. https://starwars.fandom.com/wiki/Reproduction/Legends
Most posts go to "noo!!! he has nothing between his legs!!" or "sticky fingers laffo!", and only a few go to my desired "Zabrak have a second retractile dick under their chins" or "Maul learned a lost Sith technique called Telekilingus."