Dusty Luster

A dusty luster is a name given to a vagina that hasn't been used in a long length of time.

Dave: "Yo, Kev, I had sex last night!"
Kev: "Sick mate, how was it?"
Dave: "It was good, although, she did have a bit of a dusty luster..."

Because the female had not had sex in a long time, she had quite a dusty luster