The extremely hard squeezing of the male nipple (usually)and then twisting until the person starts screaming like a pig and starts to cry because of the pain. This is because you have just crippled the shit out of his nipple.

Anatidaephobia is defined as a pervasive, irrational fear that one is being watched by a duck. The anatidaephobic individual fears that no matter where they are or what they are doing, a duck watches.

Anatidaephobia is derived from the Greek word "anatidae", meaning ducks, geese or swans and "phobos" meaning fear.

To bite a chicks nipple to hard and end up hurting her

The same thing as a Titty Twister or even a Purpler Nurple.
When someone surprises you by twisting your nipple round painfully.

When you finish your after sex cig and put it out on the bitches/dudes nipple.

Someone who has no feeling in their nipples; someone with full nipple paralyzation.

Someone who has lost feeling in their nipples.