the natural phenomena occuring in teen males roughly between the ages of 13-17. the said phenomena occurs when the male nipple and the immediate area behind it develops a hard tissue in the form of a ball, sans "Nipple Ball." this "ball" generally stays for the duration of puberty and is extremely sensitive to touch, especially titty twisters, which in some cases, have been known to cause cancer in men with nipple ball. if you are affected by nipple ball, keep them safe at *ALL* costs.
*Note: Nipple Ball generally affects 1 nipple far worse then the other, but still occurs in both.
Toby: Hey, what the fuck is this hard thing on my nipple? It hurts like a mother fucker when I touch it.
Gomez: That's called Nipple Ball you twat! Now watch this as I titty twist it and effectively end your chances at ever procreating.