hmmm. i know theres some thing for kids that suck their thumbs... the parents put this nasty tasting stuff on their kid's thumb, and it stays there... and the kid would always get this nasty taste in their mouth when they tried sucking it.

if you get your hands on this stuff, try putting it on your fingertips... when you go in for the bite, you should be sickened by the awful taste.

who knows, could to the trick.