Not admitting that you just hit yourself in the balls with nunchucks and that maybe it was a bad idea to be handling them, but instead somehow insisting that it was on purpose as a test, or a part of your special move.
Telling people about it when you could keep it a secret. lol
Doing it a second time, and on camera ;-)
Hitting yourself in the face with glowsticks, consequence black eye ow :)
From personal experience i can say hitting yourself in the balls with a Bo staff.
Now that you know it's an effective attack to hit someone in the nuts with nunchucks, hopefully you can do it as a means of self defense...
As far as your question, I'd imagine doing so in front of a bunch of people, or if you hit yourself while you were naked and someone saw.
Explaining it to your doctor.