These responses are regarding my Prince Albert piercing at 8 guage:
1. Does it hurt when getting pierced in the cock or balls?
Everyone's pain threshhold is different. My PA piercing hurt during the split second the needle went through. I think a big, hollow, needle going through anyone's skin should be expected to hurt a bit. After a few seconds, literally about 5, there was never any more pain. Getting a sleep boner can be a little uncomfortable, but, instances of that subside after just a few nights.
2. Do they numb the area before they pierce you?
No. Non-prescription anesthetics are not sufficient to numb the tissue underneath the skin. Though, I'm told some piercers use it anyway. My piercer told me it wouldn't have time to make a difference with mine.
3. Does cock size matter?
Cock size only matters with regard to the jewelry size one wears. There needs to be enough room to accommodate the full erection. Experienced piercers will measure and make recommendations if one does not know the correct jewelry size.
4. Getting hardons with a piercing hurt in underwear?
Sometimes there is a bit of discomfort when the jewelry is twisted in the wrong direction, or caught up in the underwear somehow. A simple adjustment resolves the problem.
5. Do you get infections from having a PA?
I've often read that PA's are least prone to infections because they are constantly irrigated with one's own sterile piss. That's also the reason they rate highly for quicker healing than other body piercings. Infections are always possible with physical injury. Diligent aftercare reduces the risk. I've never personally encountered anyone who told me he had infection(s) with his PA.
6. How old were you when you got your cock or balls pierced?
35