Nipple piercing is always going to be painful, no matter what precautions are taken. Many body piercers will recommend taking over-the-counter pain reliever before their appointment, or use numbing sprays or pain reducing pads, that can help reduce the pain you will feel. But when that moment comes, and the needle pops through, you will definitely feel the pain. From experience, I can tell you that it is a very intense pain indeed.
As body piercers already know, during nipple piercing, there is a strange phenomena that occurs, causing you to feel much more pain from the second nipple being pierced than you feel from the first one. This is mainly due to the body’s reaction to the first body piercing, and the body’s defense mechanisms involved in our ‘fight-or-flight’ reaction to trauma. If your piercer does not prepare you for this (many piercers do not tell the customer, fearing the customer will back out of the procedure), be prepared. For this reason, I try to always arrange for both nipples to be pierced simultaneously, avoiding the additional pain incurred when doing one nipple at a time. If you are considering getting your nipples pierced, ask your body piercer if you can have them done at the same time. There may be a slight additional cost over the standard body piercing rate, but the pain saved is worth it.