first, I'd like to see your new tattoo as well. My daughter (19) got one last Fall on her lower right back (moon and stars) and it wasn't the end of the world. Somehow the tattoo thing hit my Dad's generation (not him personally) of WWII vets and skipped mine.
Second, I'm gonna put on what my younger kid calls my "Dad Hat" and tell you TWO IS ENOUGH!! Anymore and you drift into biker-chick territory.
Bear in mind that not all guys you might be interested in want a tattooed girlfriend/wife, and, PamAnderson notwithstanding, most guys are turned off by too many.
You're better off getting (non-radical) piercings if you MUST do more stuff, because at least those leave few traces when you get sick of 'em. Of course, not everyone gets the message and some folks just keep pushin the envelope. For some examples, type "body modification" into Google and take along a barf-bag...