The TummyToys clasp is so simple: you just slide it through the piercing and snap it shut. TummyToys are specifically made for belly and body piercing. Beware of cheap imitations which are really just earrings with a heavier post...
14K solid rose gold Tummytoys belly sleeper ring with rainbow CZs, 14 ga
14K solid yellow gold Tummytoys belly sleeper ring with ruby CZs, 14 ga