yes, if this has happened you should also watch for infection
I would press charges. That is abuse.
puberty
The same as if you flicked a straight guy's nipple. If it's sensitive they jump, if they don't like it, they deck you. Whatever.
Stimulate it.
No
yes they will be hard
Your eather horny or cold!
You get cold, or stimulate them mentally or physically.
Guys LOVE Hard Nipples. It Is Easier For Them To Suck On And Wrap Their Tongues Around!
About as harmful as getting a hard nipple.
Mine seem too!