The middle finger, so that he can't even do the gesture 
What precautions do they need to take if he's already castrated? They got nothing to worry about, unless he uses a strapon.
Or his mouth...
What precautions do they need to take if he's already castrated? They got nothing to worry about, unless he uses a strapon.
Or his mouth...Criminals who have been castrated must be shipped off to labor colonies and they should not be allowed in the general public ever again. Even without a penis, they can be a threat. Castrated criminals might harbor extreme hatred for their victims, and they should not be allowed to take out retaliation against the victims or the cops who arrested them.