curb test
A test you give a girl to determine whether or not she's old enough to have sex with.  Basically you sit her on a curb, and if her feet touch the ground you're good to go.  It's really just a joke...nobody has ever been known to actually use this with the exception of R. Kelly.
Until Aaliyah could pass the curb test, R. Kelly had to settle for a good ol' date with Jill every night.