The ability to have more than one than one orgasm in quick succession.
Women can experience them far more easily than men. Men usually only have the singular orgasm because neurologically, males have connected orgasm to ejaculation. There are unconfirmed reports that say male multiple orgasms are possible... after a period of untraining the connection between ejaculation and orgasm-ing ...
Multiple orgasms require continued sexual stimulation after the first orgasm ... hmm ... lucky women -- why do we treat them so well?