Just quickly lean towards their hand and snap your teeth like you’re going to bite. Works with all sorts of unwanted touching, just be ready to actually bite if they’re also nuts and try again to call your bluff. Even if they get angry they’re much less likely to want to throw hands with the high possibility of getting bit hanging in the air.

The downside is you will look even more insane than with just fork stabs, but on the plus side you will look insane enough people will stay the fuck away in the future too