It is said by a wise few that all things should be taken in moderation. In the case of how many body piercings a person should have done at one time, moderation is also best. While you may feel the urge to try to get a tongue, lip and navel piercing out of the way and get them done in one session, it is truly best (and safer) to wait and do them in separate sessions.
One of the reasons this is the best approach is because no matter how seasoned a piercing devotee you may be, your body goes into a slight form of shock each time you are pierced. Assuming your body piercer is using sterile body piercing supplies and is properly licensed to do the procedure, by getting pierced you are exposing your body to a procedure that involves puncturing the skin (at least), and usually involves rupturing tiny blood vessels beneath the skin as well. The loss of blood during any single piercing maybe be minimal, but combined with other piercings done within minutes of each other, can add up. Also, the regenerative energy necessary for healing is compounded when you have more than one active site on the skin that requires healing. Your piercer should recommend that you spread your piercings out over time. If he/she doesn’t suggest it you should take the initiative and show self-restraint and wait. You and your body will be glad you did! 🙂