Twist, turn, pinch, pull, and every other action that can be done to a nipple in a minimal time, or all at once.
One of many things that a girl wishes upon her boyfriend when he is a jackass. That he will not find pleasure, but pain in them. Just for someone to twist them so hard that they moan, groan, cry, and almost die from the excrutiating feeling.
Or something that guys do to other guys that are walking around with their shirts off when it isnt even hot outside (but probably freezing).
"I'm going to purple nurple him so hard that he wont ever want to take his shirt off again"