Tasers are the ones that shoot. So no need :D
But For a stun gun that needs to make contact, Since it follows basically the closes conductor (For example, I broke off the 2 metal plates on my stun gun on accident, so when I shot it it directed about 4 inches forward, and around to my hand)
You can make some kind of closing mechanism so when it follows to the magnet it closes and goes forward, something like this.