Well, my kink friends do it as part of a scene. My partner is known for doing PAs on guys with a nail, board, and hammer--has not done this to me yet, but our friend he did it too last loves it and saids it made his cock act like he was 18 again.
I have been toying with the idea of getting starting a jacob's ladder, but will probably just go for a scrotum piercing here soon. Love my nipple piercings that my partner did for my about a year ago-- no nails, just regular piercing needles.
Who ever does it--professional or part of play scene--make sure they know what they are doing, and do the right after care!