How do you make your dragon have the attack pigs in Maplestory

You probably have magic missile right about then. Press "K" and look for magic missile, make sure it has at least 1 skill point put into it before you use it, click on the skill icon, and press the button below Backspace. There should be a keyboard.
Click the skill on any button you'd like and press that button to use it. I'd recommend CTRL because the attack that your staff/wand makes doesn't do much damage.